Using features of a Creole language to reconstruct population history and cultural evolution: tracing the English origins of Sranan

1. Introduction

Indentured servants, including exiled political prisoners and those who willingly entered servitude in search of a better life, were the primary source of English migrants to the British colonies during the seventeenth century [1]. Between 1645 and 1650, the English Civil War led to the exodus of at least 8000 indentured servants to the West Indian colonies, a movement of labour that coincided with the sugar boom of the 1640s and 1650s [2]. Suriname was one such English colony from 1650 to 1667, before being ceded to the Dutch. In that period, a Creole language known as Sranan (or Sranan Tongo, ‘Surinamese tongue’) developed and has survived to the present day. Most of the basic words in modern Sranan have English origins; the lexical sources of a 200-word basic vocabulary list are English (77.14%), Portuguese (3.7%), Dutch (17.58%) and African (1.59%) [3]. However, after the Suriname colony was ceded to the Dutch in 1667 under the Treaty of Breda, there was no further significant contact with England or the English, and, in the years after this cessation, the population of English people in Suriname dwindled to only 39 individuals [3–6]. Therefore, the English features presently found in Sranan were likely introduced during the 1650–1667 formation period. Of course, we cannot be certain that particular features of Sranan are inherited from seventeenth-century English dialects, rather than from, for example, internal linguistic developments within Suriname over the intervening centuries, other European or African languages present in the early period or, indeed, recent movement of people between Suriname and neighbouring Guyana where a related but distinct Creole with English vocabulary is used. However, as outlined in our Material and methods section, we have attempted to reduce the likelihood that alternative accounts are more plausible than that of seventeenth-century origins.

As Creole languages primarily develop out of contact among speakers of several languages, studies of Creoles typically attempt to specify the origins of specific linguistic features found in a particular Creole. Multiple hypotheses have been proposed to account for the processes of the formation and transmission of Creoles [3,5,7–18]. Alleyne, in his work, Comparative Afro-American [19], even while arguing for a predominantly African rather than English origin for the features in Atlantic Creoles such as Sranan, accepts the importance of English regional dialects in the Creole language formation process. In doing so, Alleyne proposes, for consideration, an early version of what we term the pan-dialectal (PD) hypothesis when he states, ‘one would have to consider a whole range of dialects from the period, particularly those in the port areas of Bristol, Liverpool, etc.’ (p. 224). The pan-dialectal hypothesis suggests that many English dialects influenced the formation of Sranan.

Another type of PD hypothesis crops up, as well, in work which argues the opposite position on the centrality of English influence in the Creole formation process. In The ecology of language evolution [20], Mufwene proposed an analogy between languages and biological species, which he applied to the origins of Atlantic Creole languages such as Sranan. A major facet of this analogy is the hypothesis that the features of a Creole language could be the ‘fittest’ of the ‘gene pool’ of linguistic features of the European language that is the main source of the Creole vocabulary. Thus, from Mufwene's perspective, the seventeenth-century dialects of English in England would have created in Sranan a situation that would favour ‘the more salient, more regular, or more transparent alternatives winning over the less common, less transparent and less salient alternatives' [20, p. 57]. By implication, the entire pool of linguistic features introduced by English migrants, irrespective of how large or small in number or influence the users of a particular feature might be, constituted the feature pool. This represents Mufwene's broad version of the PD hypothesis.

We can test this PD hypothesis only after we add specificity to the hypothesis, even to the point of adding details that are not explicitly specified by Mufwene or others. First, the linguistic features undergoing competition and selection may be ‘words, pronunciations and grammatical rules' [21], whereas the present study is concerned largely with pronunciations of words, and not with grammatical rules. (For a recent study of the latter, see [21,22].) Second, for a given set of languages and language features, Mufwene's theory is open as to the relative impact of key non-linguistic influencing factors, such as the numbers of speakers or the number of languages in the contact situation employing a specific feature, and the number of interactions among speakers. In the present study, we ‘close’ some of these theoretical aspects by adding assumptions to the Mufwene version of the PD hypothesis, so as to render it testable with the present data. The resulting models of linguistic ‘selection’ in the contact situation are perhaps oversimplified realizations of Mufwene's theory, but we hope that testing these models will clarify the role of some of the relevant factors.

In the more extreme framing of the PD hypothesis, all features across all dialects in England were in competition within the ‘gene pool’ of linguistic features, with some more ‘fit’ dialect features inherently more likely to be included in the Creole. Thus, this hypothesis posits that the relative abundances of different English dialects in the migrant group would be unrelated to the likelihood that features of these dialects are present in Sranan. Instead, features that were more common across English dialects, more common across human languages or more similar to features of the West African languages in the contact situation would be more likely to become part of the Creole, even if these features were rare in the migrant population of English origin. In the second and less extreme framing of the PD hypothesis, the likelihood that a particular feature of English dialects occurs in Sranan would be proportional to the number of speakers with that feature living in Suriname and, therefore, would be positively related to the frequency of the use of the regional dialect feature during the formation period of Sranan.

A sharply contrasting hypothesis, that of the emergence of a standard dialect (SD) from the dialects of a specific region, hereafter the SD hypothesis, has been suggested by Smith [23,24]. According to Smith's proposal, English in the seventeenth century was undergoing a standardization process focused around the forms of speech in southeastern localities in England. This meant that speakers from all localities across England were becoming familiar with the emerging SD of London and the southeast and would use it to communicate with people who were not from the local community of the speaker in question. Thus, when speakers from various regions in England mixed in Suriname, they would have opted for forms approximating this emerging standard that had started to form in England. In this view, the origin of Sranan's seventeenth-century linguistic features was Early Modern (London) English [23,24], which would constitute an SD based on a regional dialect of the southeast. By contrast to the PD hypotheses above, this SD proposal suggests that the features of English that are included in Sranan do not represent either the most ‘fit’ features or the most common features of the dialects spoken by the migrants to Suriname. Instead, the features of English incorporated into Sranan represent those of a single emerging standardized version of English based in the southeast region in and around London, and this version being chosen as the preferred mode of communication when members of different dialect groups interacted with one another in the Caribbean and Suriname.

Here, we propose an alternate hypothesis that generalizes the regional element of the SD hypothesis: the sources of the linguistic features surviving in Sranan are neither from all over England nor from a standardizing London version of English, but instead reflect the influence of a small number of specific communities, districts or regions that may include London and southeast England. Dialects of English within England today vary considerably from one (sub)-region to another, and this variation was likely even greater in the seventeenth century. However, if some subset of dialect features (e.g. the ‘fittest’ features) has been relatively stable within England, then it might be possible, using modern English dialect data, to statistically detect a signal of the specific local and regional English dialects that most influenced the origins of Sranan, whether these be in the southeast or elsewhere. We refer to the possibility of such signals as the multiple specific sources (MSS) hypothesis. To test whether the MSS hypothesis is supported over the PD and SD hypotheses described above, we compared Sranan word-forms with those of cognates across twentieth-century dialects of English in England. To do this, we compiled data on Sranan, primarily from the Dictionary of Sranan Tongo [25], and data on the dialects of England from the Survey of English Dialects (SED) [26]. This survey, covering 313 localities across England and the Isle of Man during the mid-twentieth century, is considered a gold standard for regional dialect surveys of spoken language. Of particular importance to the present analysis are the measures taken by the SED to survey only those persons who were most likely to preserve the ‘traditional dialect’. Given these measures, which are outlined below, we propose that our understanding of the evolution of Sranan can be advanced by the use of the SED as a proxy for seventeenth-century English.

What is the role of geography in Creole formation? The PD hypothesis contains no explicit claims about the role of geography in the selection of features from source languages that are incorporated in the formation of Creoles. However, the available historical data on the geographical origins of migrants from England in seventeenth-century Suriname allow us to examine the role of their geographical place of origin in the formation of Sranan, and the SED gives us information about the relative frequency of particular linguistic features across regional dialects. Accordingly, we attempt to derive, under the PD hypothesis, reasonable and testable implications about the role of geography. Under this hypothesis, the likelihood that a given linguistic feature occurs in Sranan is positively related to the frequency of the dialect feature: (i) in the more extreme version, across all of the dialects and languages that may have contributed to the formation of Sranan and (ii) in the less extreme version, within the speech of the group of migrants present in the formation period. As noted earlier, under the more extreme version, the likelihood that a given feature would occur in Sranan is unrelated to the frequency of that feature within the dialects of the migrant group and, therefore, is unrelated to the frequencies of dialect locations represented in the migrant group. In other words, in the more extreme version of the PD hypothesis, the geographical origins of the English-speaking migrants to Suriname would not be related to feature formation in Sranan.

In the less extreme version of the PD hypothesis, we expect that the likelihood that a feature would occur in Sranan is related to its frequency in the migrant population. Given the well-known evidence of significant variation in dialect features across geographical locations in England and Wales, the frequency of a feature in the migrant population is likely to depend on the locations from which the migrants originated; thus, the geographical origins of the migrants to Suriname from England would be related to the feature formation within Sranan. Under the other hypotheses introduced above, namely the SD and MSS hypotheses, the dependence of feature formation within Sranan on geographical location is explicit, because these hypotheses propose that either the convergence among the English-speaking migrants in Suriname to the dialects spoken in a specific region of England (London and the southeast) or the geographical origins of migrants, directly influenced Sranan's formation. In what follows, we will consider various ways of establishing the relevance of geography in Creole formation.

2. Material and methods

There are no spoken language samples of the seventeenth-century migrants from England. However, from the SED, we have samples of English from the middle of the twentieth century, 300 years later, taken primarily from rural areas with stable populations and mainly from working men and women whose grandparents were born in the same area [26]. The SED describes language features of 313 locations selected for geographical spread and representativeness, from across England, some parts of Wales, the Isle of Wight and the Isle of Man. These locations were chosen, not because it was thought that there was some definite number (e.g. 313) of English dialects, but rather to ensure a relatively even spread geographically and across established administrative county entities in England. Labelling these as ‘dialects' is based on the fact that no two of the 313 locations produce an identical combination of variants for the hundreds of linguistic variables included in the SED. Therefore, each variant combination is unique to a particular one of the 313 geographical locations and can be regarded as belonging to and identifying each of these geographical locations. (Although it would be more appropriate to refer to the speech sample at each location as a ‘lect’, we use ‘dialect’ herein for the sake of convenience.) The aim of the survey was the elicitation of archaic, ‘lexical features … in the form of … phonological variants … and grammatical features’ [26, p. 45]. In this survey, the researchers took as their target population ‘men and women, sixty and over … because they were considered to be more likely to best preserve the traditional dialect; [and therefore] … the questionnaire [used in the SED, was] … constructed for the farmer’ [26, p. 44, 46].

As is the case with the English dialects, there are no seventeenth-century data for the earliest forms of Sranan Tongo. This study, therefore, relied on the Dictionary of Sranan Tongo, documenting the vocabulary of modern Sranan Tongo, supplemented by a number of early eighteenth-century wordlists documenting sometimes archaic speech forms. These documents, alongside Smith's [23] historical phonology, provided information regarding the etymology of the English origin words in Sranan, the phonological processes they went through while being adapted into Sranan and sound changes they may have gone through since [27]. Using these sources [25,28–31], we checked for all words in Sranan of potential English origin. In addition, words similar in form and meaning across Sranan and English were checked with dictionaries of the other European languages known to have influenced Sranan, notably Portuguese and Dutch [32,33], to eliminate words that could possibly have originated from these languages as opposed to English.

We then went through the word list compiled from the above-mentioned Sranan sources against the SED's Index of Keywords [26] and their lexical and phonetic regional variant forms. Where no match was found, actual keyword headings in the books of SED responses [26] were checked for any variants that might match items not found in the Index of Keywords, because regionally variable realizations of a given etymon were not always presented in this index. When no SED entries could be matched to a Sranan word form, we removed that word from the wordlist. We then pared down the resulting list of 497 Sranan–English matching items to remove those that showed no linguistic variation across the English dialects surveyed in the SED in the features of interest. Through this process, we identified 45 Sranan words that matched an entry in the SED for which there was relevant variability across 313 localities in twentieth-century English dialects [26]. (Although each of the 313 dialects has a unique combination of features in the SED, we found two dialects that are identical in this much smaller dataset, Ullesthorpe and Carlton Curlieu, both in Leicestershire.) These 45 words were grouped according to their variable phonetic features:

• a. Variation in post-vocalic rhoticity (±PVR), e.g. ‘burn’ [bn] or [b_n],

• b. Variation in word-initial phonemic /h/ ([h]∼[j]∼[w]∼Ø), e.g. ‘hot’ [ht] or

  [ _t]; ‘help’ [hɛlp], [ _ɛlp] or [jɛlp]; ‘woman’ [hman], [wman] or [_man]

• c. Variation with /f/ and /v/ (±labial voicing), e.g. ‘four’ [fo] or [vo],

• d. Variation with /θ/ and /f/, and /ð/ and /v/ (±labial), e.g. ‘broth’ [bf] or [bθ] and ‘brother’ [bd], [bð] or [bv],

• e. Variation with [j]∼Ø (±word-initial palatal), e.g. ‘yesterday’ [jɛstde] or [_ɛstde],

• f. Variation with word-final [ks]∼[sk] (±consonant cluster reversal), e.g. ‘ask’ [a:sk] and [aks],

• g. Variation between forms approximating [o] and those approximating [au], e.g. ‘old’ [old] or [auld].

From these data, we constructed a reference dataset that includes all of the recorded SED phonetic forms from the 313 localities for each of the 45 items, as well as the phonetic forms found in Sranan for each of the 45 items (see table 1 and electronic supplementary material, table S1). As can be seen in table 1, an ‘item’ is a Sranan word, expressed in English orthography, plus an associated phonetic option or ‘slot’ that can be coded on a binary (0/1) scale. For 33 of the 45 items, the phonetic option referred to the pronunciation at a single word location, e.g. word-initial [h], coded as ‘1’ if +[h], and as ‘0’ if –[h]; or rhoticity, coded as ‘1’ if +[r], and as ‘0’ if –[r]. Thus, for each of the 313 SED locations, and for Sranan, the item, ‘house’, varying in word-initial ±[h], is coded ‘1’, if in that dialect ‘house’ is pronounced with a word-initial [h], e.g. [has], and ‘0’, if it lacks the word-initial [h], e.g. [as]. These two options associated with ‘house’ are referred to as linguistic ‘features’ (occasionally, ‘variants’). For simplicity, we adopted the convention throughout of assigning the code of ‘0’ whenever the feature in question was not produced in the interview data for a given SED location. For example, in the pronunciation of ‘hog’, a ‘0’ is coded both in localities where ‘hog’ is pronounced without the initial [h] sound and in those where ‘pig’ is the choice of lexical item rather than ‘hog’.

For the remaining 12 of the 45 items, the phonetic option was derived from the pronunciation at two word locations. For example, the word ‘ask’ was coded according to word-initial ±[h] and word-final [ks/sk], and the word ‘hurt’ was coded according to word-initial ±[h] and rhoticity. In these cases, the four possible combinations of two pronunciations at each of two locations were reduced to a binary option by assigning ‘1’ to a dialect (including Sranan) if the pronunciation of the English reflex was the same as that of the Sranan word; and ‘0’ if the pronunciation of the English reflex differed at either location from that of the Sranan word, or if the English reflex was not produced in the dialect. In summary, the linguistic profile of each locality, including Sranan, is represented in the dataset as a 45-element row vector of 0s and 1s, according to the linguistic features of the dialect of that locality.

The similarity between two dialects can be defined in terms of the 45-element vectors representing the dialects. Here, we adopt the simplest definition of similarity as ‘per cent agreement between two vectors'—i.e. the number of positions at which the two vectors have the same element, 0 or 1, divided by 45. Because we are treating the SED speech forms for each locality as a proxy for the seventeenth-century English speech forms produced for that locality, we regard the SED dialect (defined as speech forms for each locality) with the highest per cent agreement to Sranan as being most likely to be among the set of source dialects for Sranan. The technical assumption justifying this use of the SED as a proxy is that if the (unobserved) seventeenth-century English dialects were ranked according to their (unobserved) similarity to Sranan, that ranking would be similar to the ranking of the (observed) corresponding SED dialects with respect to their (observed) similarity to Sranan. While we have no empirical support for or against this assumption, we believe that, pending future work, the use of the SED as a proxy is a reasonable starting point for analysis into the origins of Sranan.

The port of Bristol was likely the main port of departure for English indentured labour to the English colonies in the Americas in the second half of the seventeenth century [34]. To compare our linguistic dataset with historical records of migration from England to Suriname, we therefore used the Bristol Register of Servants to Foreign Plantations [35] to categorize the place of origin for indentured labourers arriving in the colonies and have assumed that this sample of migrants is representative of the subset that settled in Surname. We extracted the origin and destination of indentured servants travelling between 1654 and 1666 with destinations in the Caribbean from which Suriname was settled [35]. Suriname was not listed as a destination, and the historical record is consistent with the presumption that indentured persons would have first landed at these other destinations, including Barbados, Antigua, Nevis and St Christopher [36–38].

With the 45 linguistic features from Sranan and 313 English dialects, we tested each of the hypotheses proposed in the introduction. The PD hypothesis—according to which features of English found in Sranan were either selected by the commonality criterion proposed by Mufwene or selected out of the entire range of local and/or regional dialects and thus likely sampled in proportion to their frequency—implies that these selected features would be the ones most common across the various dialects at the time. By extension, these same features might be the ones that are most common across modern dialects. Note that this method can give us insights into whether frequency-dependent feature selection might have occurred, but it cannot account for other factors that might influence whether a feature is selected, such as prestige of the individuals with certain features. With this proxy, we first tested whether the most common variant of each linguistic feature was predictive of the variant in Sranan.

Next, to test the alternate framing of the PD hypothesis, we combined the linguistic dataset with the information from the Bristol Register to test whether features of Sranan were predicted by the most common linguistic variant from regions of England that were likely source locations for migrants. Third, to test the London/southeast SD hypothesis, which posits that a standardized version of London English would be most likely to contribute language features to Sranan, we compared Sranan with the two modern London/Middlesex dialects in the SED. Fourth, to test our MSS hypothesis that Sranan was shaped by a relatively small number of source dialects from regions of high migration to Suriname, we compared Sranan with each local dialect in turn and found the one with highest overlap of language features. We then determined whether input from another local dialect would substantially improve the overlap with Sranan.

In addition, we examined whether the distribution of the dialects in linguistic space is ‘similar’ to the distribution of the corresponding locations in geographical space. We first reduced the dimensionality of our language dataset by performing a principal components analysis [39] on the data matrix of binary features for English dialects and Sranan, and extracting the first four principal components (PCs). Then, to quantify the similarity in ‘shape’ between the linguistic and geographical distributions, we created a two-dimensional linguistic distribution using the first and second PCs, and compared it to the two-dimensional (latitude and longitude) geographical distribution of the dialects (excluding Sranan, the geographical coordinates of which are an outlier in the present context). The comparison was done using a Procrustes analysis [40,41]. Specifically, after Procrustes analysis, we denoted by D the minimized sum of squared Euclidean distances, scaled to have minimum 0 and maximum 1, between the linguistic and geographical representations of the SED dialects, and calculated a similarity statistic, . We then calculated empirical p-values for these t₀ values over 10⁶ permutations of geographical locations, thus determining how likely it would be for any random assignment of geographical locations to be more similar to the language-feature PCs than the actual dialect locations. A significant association between language features of local English dialects and their respective locations would provide support for hypotheses that link the emergence of the linguistic features of Sranan to the geographical origins of the speakers of English who lived in Suriname in the seventeenth century. The SD and MSS hypotheses, as well as the less extreme version of the PD hypothesis, are examples of such hypotheses, whereas the more extreme version of the PD hypothesis is not.

Finally, with the presence and absence of the 45 features as input data, we constructed a language phylogeny that included English dialects and Sranan using TreeMix [42]. From the input data, TreeMix constructs a maximum-likelihood phylogeny in which dialects that share more features should be closer together on the tree. The algorithm then tests for statistical support for migration/mixture events between branches. For example, in genetic analyses, an admixture (or migration) event between two distantly related populations would result in offspring that have some stretches of DNA that are more closely related to one population and other stretches of DNA that are more closely related to the other population. In a traditional phylogenetic analysis, an admixed sample might be difficult to resolve but would likely appear near one of the two parental populations on the tree; however, it might seem to be somewhat distantly related to that parental population because large parts of its genome are more closely related to a different population. In this case, the ancestry of the admixed sample is better explained by input from two independent populations. Thus, TreeMix tests whether branches on the tree are better explained by hypothesizing input from another branch on the tree, and it draws an arrow connecting branches when these putative migrations significantly improve the likelihood score of the tree. This type of analysis can also be performed with our language features as inputs instead of genetic data: specifically, language features are treated here as analogous to genetic alleles or polymorphisms, dialects are treated as analogous to genotyped populations and branch length represents linguistic distance instead of genetic distance. This analysis is useful for our discussion of Sranan, because it provides another way to test whether the features of Sranan are better explained by multiple specific dialect inputs (inferred, for example, when a migration event to the Sranan branch improves the likelihood score of the tree) than by just one dialect input (e.g. when there is no statistical support for a migration event to the Sranan branch).

3. Results

(a) Comparison to historical records

In 1650, Suriname was settled from other English colonies in the Caribbean, including Barbados, Antigua, Nevis and St Christopher. We used the Bristol Register of Servants to Foreign Plantations [35] to establish the origins within England of persons migrating to these colonies, and we assume that this sample of migrants is representative of the subset that settled in Suriname. Of the 3077 persons with destinations listed as English colonies in the Caribbean, 1410 have their places of origin listed; those locations that could be assigned to specific locations in England are listed in table 2 and visualized in figure 1. Bristol and the surrounding counties contribute 64% of the indentured servants whose place of origin is recorded, and counties in Wales contribute another 11.7%; the remainder of the indentured servants originated primarily from counties in the East, South and West of England (see figure 2 for regions).

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Table 2.Origin locations of indentured servants from England listed in the Bristol Register, 1654–1666. Locations near Bristol and the surrounding counties are highlighted in bold; locations in Wales are noted in italics.

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location of origin	no. servants	percentage
Somersetshire	208	14.8
Bristol	152	10.8
Gloucestershire	149	10.6
Monmouthshire	137	9.7
Wiltshire	108	7.7
Herefordshire	82	5.8
Glamorganshire	73	5.2
Devon	39	2.8
Dorset	27	1.9
London	39	2.8
Carmarthenshire	36	2.6
Shropshire	33	2.3
Worcestershire	32	2.3
Pembrokeshire	30	2.1
Brecknock/Brecon	26	1.8
Cornwall	15	1.1
Hampshire	11	0.8
Middlesex	10	0.7
Oxfordshire	10	0.7
Staffordshire	10	0.7
Kent	8	0.6
other locations	175	12.4

With this distribution of origin locations from the historical record and the dataset of language features from Sranan and 313 dialects of English, we tested the proposed hypotheses. First, we note that the English features of Sranan are not identical to any one local dialect of English. One prominent feature characterizing English dialects is the production or non-production of the /r/ sound after vowels (post-vocalic rhoticity). In general, many modern dialects of English tend to show either predominantly presence or predominantly absence of post-vocalic rhoticity; however, Sranan shows evidence of influence from both rhotic and non-rhotic dialects. For example, the Sranan word [moro] (more) suggests that the English input forms had a post-vocalic /r/. However, other words in Sranan such as ‘four’ [f] suggest that other English input forms lacked a post-vocalic /r/. This pattern is also observed in Saramaccan and Aukan, two other Creole languages in Suriname that derive their vocabulary from English and whose histories overlap with that of Sranan.

For rhoticity in particular, we must observe the caveat that dialects in the 1950s, including those sampled in the SED [26], might have different features from dialects in the seventeenth century. While the loss of rhoticity in English dialects became common after 1790, there were sporadic losses of /r/ sounds beginning in the 1300s and a more general weakening of /r/ from 1640 onwards [43]. Furthermore, there is evidence, such as from studies of rhyming, that the early losses of post-vocalic rhoticity were occurring in at least some regions that are non-rhotic in the SED [44]. For example, Wyld cites many instances of r-loss from the years 1441 to 1674 and states that ‘it would appear that the weakening and disappearance of r before another consonant, especially, at first, before [s, ∫], had taken place by the middle of the fifteenth century at any rate in Essex and Suffolk, that a hundred years later London speakers of the humbler sort (Machyn), as well as more highly placed and better educated persons in various walks of life, pronounced the sound but slightly, if at all; that the tendency is more and more marked, not only before [s, ∫], but before other consonants also, until by the middle of the next century it seems that the pronunciation among the upper classes … was very much the same as at present’ [45, p. 299]. More recently, a Cambridge University survey of diversity of English in England has suggested that rhoticity has declined rapidly since the 1950s because of the influence of the non-rhotic dialects of London and the southeast [46]. Finally, although the SED data for each location generally include multiple subjects who were chosen carefully and interviewed thoroughly, we must also note the caveats that (i) no single set of features can accurately summarize the natural variation in a dialect or language and (ii) we cannot account for contact- and context-dependent dialect changes that might occur when individuals interact in a new location.

To the extent that it is possible to test alternate hypotheses of the origin of linguistic features in Sranan using the modern lexical data, we find substantially more support for our MSS hypothesis than for the previously proposed PD hypothesis or SD hypothesis. In the simplest version of the PD hypothesis, the variant of each binary linguistic option that is found in Sranan is predicted to be the variant that is more frequent across the 313 SED dialects. We found that the per cent agreement, across the 45 linguistic options, between the Sranan variant and the modal variant was 33%. Because of the spatial correlation among dialects, we have no simple formula for calculating a confidence interval for this percentage. However, we developed a bootstrapped interval by sampling 313 dialects with replacement from the SED set, calculating the per cent agreement on each sample for a total of 10 000 samples and then extracting the 2.5th and 97.5th percentiles from the bootstrapped percentages. The resulting bootstrapped 95th per cent confidence interval is (31.1%, 42.2%). We use this interval as the basis for a rule-of-thumb: differences of approximately 10% or more in per cent agreement are substantial. Applying this rule to the percentages in table 3, we conclude that restricting the dialects used to compute per cent agreement to those dialects from (i) regions contributing at least 5% of migrants, or at least one migrant, in the Bristol Register (alternate versions of the PD hypothesis) or (ii) Harmondsworth or Hackney in the Middlesex/London SED region (alternate versions of the SD hypothesis) does not increase the per cent agreement substantially. By contrast, restricting the comparison set to a single local dialect increases per cent agreement substantially; Blagdon in southern England was the best single match, with 60% similarity to Sranan (27/45 features). Finally, we considered the effects of incorporating two independent source dialects as inputs to Sranan, first using Blagdon to compute per cent agreement and then finding the best match to the remaining 40% of features that were not present in Blagdon. In six dialects, nine out of the remaining 18 features were present, increasing the per cent agreement substantially from 60 to 80% (table 3). Four of these additional dialects were in eastern England: High Easter, Docking, Doddinghurst and Canewdon.

Table 3.Testing hypotheses of the origin of English features in Sranan. In the last column, each of the two percentages in boldface is substantially greater than the percentages above it.

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hypothesis		similarity to Sranan
PD hypothesis (e.g. Mufwene [20])	comparison to most common variant of each feature across English dialects	33.3%
	comparison to most common variant of regions contributing at least 5% of migrants in the Bristol Register	35.6%
	comparison to most common variant of regions contributing at least one migrant in the Bristol Register	42.2%
standard London/southeast dialect (SD) hypothesis (e.g. Smith [23])	comparison to dialect from Middlesex and London SED region: Harmondsworth	37.8%
	comparison to dialect from Middlesex and London SED region: Hackney	35.6%
	comparison to dialect from Harmondsworth, then from Hackney for Sranan features not found in Harmondsworth	46.7%
MSS hypothesis (this manuscript)	comparison to most similar dialect to Sranan (Blagdon)	60%
	comparison to most similar dialect to Sranan (Blagdon), then most similar dialects for Sranan features not found in Blagdon (High Easter, Docking, Doddinghurst, Canewdon [Eastern England], Farningham [Southern England], Llanfrechfa [Wales])	80%

The hypothesis that a cluster of local dialects, other than the emerging standardized dialect from London and the southeast, is a possible source of English-derived word-forms in Sranan is supported by a geographical analysis of different types of features. When we look across all 45 features studied, dialects near the port of Bristol appear to be the most similar to Sranan (figure 1b). However, this overall similarity masks interesting regional patterns that are revealed when we examine different types of features separately. For example, as mentioned above, Sranan appears to show inputs from both rhotic and non-rhotic dialects of English. If we use only the rhotic word-forms to calculate the similarity between Sranan and English dialects, we see a striking contrast in similarity that separates the rhotic and non-rhotic dialects (figure 3a). The regions of England where post-vocalic rhoticity is common are clearly delineated by their number of matches to this set of words; in these features, Sranan matches well to the areas around Bristol, which were the source locations for many of the migrants to Suriname. An opposite pattern emerges when we calculate similarity using only the non-rhotic subset of features in Sranan (figure 3b). For these non-rhotic features, the areas in England around Bristol (starred in figure 1a) are not similar to Sranan. Thus, we predict that the non-rhotic word-forms in Sranan could have been influenced by a different subset of dialects; these could have been from Wales, eastern England or parts of northern England (see the yellow points in figure 3b). We can visualize other dialect features in a similar manner: figure 3c shows the distribution of a diphthong in words ending in ‘old’, which is present in Sranan and widespread in the central parts of England, and figure 3d shows the distribution of matches to Sranan in words including a word-initial [h] sound, which is often present in Sranan.

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In figure 3, we observe that there is a strong geographical component to the distribution of linguistic features within England; post-vocalic rhoticity, certain diphthongs and word-initial [h] forms all show geographical clustering in their presence. Our PC analysis of the raw language-feature data reinforces these findings, as can be seen in figure 4. The goal of this analysis is to reduce the dimensionality of the linguistic space from 45, i.e. the number of items on which dialects may vary in our dataset, to a much smaller number of dimensions, the PCs, such that these PCs (i) account for much of the variation across dialects and (ii) are readily interpretable in linguistic terms. The interpretation of the PCs naturally depends heavily on the phonological features of the 45 items used in the analysis, and it would be expected to change if, for example, a different distribution of features were used, or if lexical items were added. As can be seen in table 1, 28 of the present 45 items contained ±[r], 14 items contained ±[h], three items contained ±[au] and three items contained ±[f].

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The first principal component (PC1) extracted from the data explained 39.2% of the variance in features across dialects. An examination of the coordinates of the 45 items in figure 4b shows that, in general, rhotic items load positively and non-rhotic items load negatively on PC1. Thus, this first principal component combines the rhotic features highlighted in figure 3a and the non-rhotic features highlighted in figure 3b into a single bivalent dimension that can reasonably be interpreted as ‘rhoticity’. This finding is not surprising, given that more than half of the items contained ±[r]. The second principal component (PC2) in figure 4b explained 11.1% of the variance in the sample, and it was strongly correlated to features describing the presence or absence of the word-initial phonemic ±[h], i.e. the features highlighted in figure 3d. In figure 4a, we plot the 313 SED dialects and Sranan in this two-dimensional linguistic space (rhoticity, h-fullness), the dimensions of which together explain 50.3% of the variation among dialects. The PC1 score of a dialect can be viewed as the extent, ‘averaged’ mainly over the 28 items containing ±[r], to which the dialect is rhotic versus non-rhotic; and the PC2 score of the dialect can be interpreted similarly in terms of h-fullness. It can be seen in figure 4a that Sranan is closer to Blagdon (ID = ‘240’) and other dialects in the South (see figure 2 for the locations corresponding to the IDs in figure 4a) than it is to the dialects in Essex and Norfolk. This finding is consistent with the results reported in table 3.

The third principal component (PC3, not shown in figure 4) explained 5.6% of the variance in the sample and correlated primarily to features describing the presence of the diphthong, ±[au], in words ending in ‘old’, i.e. the features highlighted in figure 3c. Finally, the fourth principal component (PC4, not shown) explained 4.5% of the variance in the sample and correlated primarily to the presence of ±[f] in words ending in ‘th’, such as ‘broth’ and ‘teeth’.

To determine whether the features of English dialects were significantly associated with their geographical location, we performed another PC analysis without Sranan, extracted the first two PCs and then conducted a Procrustes analysis (following [40]). This Procrustes analysis indicated that, for the SED dialects, the two-dimensional plot of PC1 versus PC2 was significantly associated with the geographical locations of the dialects: we found significant concordance (p < 10⁻⁶) between the first two PCs of dialect feature data and geographical locations for 313 dialects in the SED database (Procrustes t₀ = 0.46). This result suggests that there is significant geographical structuring in the dialect features, which further supports the graphical representations in figure 3.

Finally, our phylogenetic analysis using TreeMix [42] suggests that Sranan is most closely related to local dialects in Somerset (near the port of Bristol), but with strong evidence for mixture from a dialect in High Easter, Essex, in the east of England (figure 5). These results are consistent with the regions in table 3 that contribute to maximum overlap with Sranan: Blagdon, the dialect with the most matching features with Sranan, is in Somerset, and three of the local dialects that matched best to the remaining features are from Essex (High Easter, Doddinghurst and Canewdon). We note that Essex was specifically mentioned by Wyld [45] as a location where loss of rhoticity was occurring by the fifteenth century.

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This pattern was observed in multiple replications of the TreeMix algorithm. When we conduct a TreeMix analysis with one migration event allowed, the algorithm predicts a mixture from a dialect in Essex to Sranan. When we increase the number of migration events allowed, we observed additional predicted mixture events that were less strongly supported than the one involving Sranan (see electronic supplementary material, figure S1). The interpretation of these additional mixture events is unclear. For example, in one replication, an additional mixture event was signified by an arrow from Blagdon in the West to Great Strickland in the North. After the fact, we examined the PC scores of the dialects and noted that Great Strickland was placed on a branch with other northern dialects that all have roughly the same PC2, PC3 and PC4 scores. However, Great Strickland was lower in PC1 scores (rhoticity) than the other northern dialects on the branch. It is possible that the algorithm interpreted this pattern as evidence that Great Strickland was influenced by dialects outside of the northern region, but why Blagdon was the best-fit source of influence is unclear.

4. Discussion

In this paper, we performed a set of statistical analyses to compare features of a Creole language, Sranan in Suriname, with potential source dialects in English. We then interpreted these analyses alongside historical data to develop a fuller picture of the formation of this Creole.

With the obvious caveat that Sranan and all of the dialects in question have accumulated changes since the seventeenth century, we used the variation in modern dialect features as a proxy for variation in the source dialects, and we used this modern dialect data to test multiple hypotheses about the formation of Sranan. The first hypothesis tested, the PD hypothesis, posits that features of Sranan could be potentially sourced from all dialects of England in proportion to the frequencies of the features across local dialects in the early contact situation. The second hypothesis tested, that of a regional London/southeast dialect source, states that a standardized form of London English was in the process of being formed during the seventeenth century, and that dialects approximating the emerging regional London/southeast SD of English would have been likely produced when settlers from multiple dialects spoke with one another, thus influencing Sranan. By contrast, we propose a more general form of the SD hypothesis according to which Sranan was primarily influenced by MSS, which we propose to be two distinct regions of England, the southwest, Somerset in particular, and in the east, specifically Essex.

The analyses of dialect variation in the 1950s presented in this manuscript support our hypothesis: features of Sranan are not well predicted by the most common features across English dialects or by the features of London-area English, whereas these features are better predicted by the inputs from two regional dialects in English. The results of these comparisons, shown in table 3, are further supported by our statistical analyses. First, we showed that the variation of language features across the dialects of English shows strong signals of regional patterning, and that Sranan exhibits features consistent with input from multiple regions (figure 3). Of the different types of features studied (table 1), rhoticity and word-initial [h] were strongly correlated with the first two PCs of the dialect data, respectively, together explaining approximately 50% of the variance in features across dialects. Our comparisons show that Sranan was most similar to the Blagdon dialect and other dialects close to the port of Bristol, and this finding is consistent with the source locations for indentured servants travelling from England to the Caribbean (figure 1). However, some features of Sranan, most notably the lack of post-vocalic rhoticity found in multiple word-forms, suggest input from another source outside of this region. Several regions of England with modern-day non-rhotic dialects were represented in the migration to Suriname through Bristol, such as Wales and the east of England (figures 1 and 3). Therefore, dialects from these regions could be putative secondary sources for features of Sranan. These observations are supported by a maximum-likelihood phylogeny of the language features that can account for potential mixture between branches. This phylogeny suggests that Sranan is most closely related to dialects near Bristol, and that there is significant evidence of mixture with a dialect from Essex in the east of England.

It is still an open question as to whether the present data might allow us to infer the degree to which the migrants to Suriname from the different locations in England shared a rough approximation to a well-formed language variety, i.e. a koiné, out of which Sranan evolved. On the one hand, our rejection of the extreme version of the PD hypothesis suggests that the features of Sranan were not merely a random or frequency-dependent selection from the regional dialect speech of the English settlers. On the other hand, the present conclusion that there likely were two main English sources of Sranan is consistent with the view that some degree of koinéisation (i.e. of dialect levelling or linguistic accommodation and convergence) may have occurred. Resolution of this issue may depend on an analysis of the amount of variation in the occurrence of particular features, e.g. +[r], across the relevant SED items. In the present analysis, we focused on the average tendency across the relevant SED items to observe the feature, as this tendency is indexed by the associated principal component score of the dialects. An extension to the analysis of the variation in feature occurrence seems warranted.

The present basis of 45 Sranan items used to define ‘similarity’ or ‘relatedness’ among dialects is essentially phonological (rather than, e.g. lexical or grammatical). When we reduce this basis to the familiar subgroups of items, namely rhotic, non-rhotic, diphthong (±[au]) and h-fullness (±[h]), the results in figure 3a–d show, as expected, that the similarity between Sranan and a given cluster of SED dialects depends on the specific subgroup of items. This raises the question of how robust are the present conclusions about the origins of Sranan to an expansion of the basis, or set of items, used to define similarity. For example, would our conclusions change if lexical or grammatical features were included in the basis, or if, following Szmrecsanyi [22], one were to generalize the definition of similarity to include the relative frequency of each feature in the different localities, rather than the simpler binary code, ‘present’ versus ‘absent’? These questions merit consideration in future research.

Taken together, our analyses support the hypothesis that Sranan was influenced by certain distinct dialects from widely separated regions in England. To explain the features of Sranan, we did not need to invoke processes based on frequency of feature occurrence across dialects, or on the use of features of an emerging standardized English dialect based on the speech of London and the southeast. Instead, we could explain the features of Sranan by hypothesizing input from two distinct locations within England that were known source locations for indentured servants migrating to Suriname. In addition, our analyses shed light on the particular features, rhoticity and h-fullness, that explain most of the dialect variation in English, and confirm previous studies showing that this variation is significantly associated with geography [26,47,48]. In summary, our results not only provide support for a new hypothesis of Sranan's formation, but also suggest that a method of combining known historical data with statistical analyses of language features could be fruitful in future studies of Creole formation and, more generally, language variation.

Data accessibility

The datasets supporting this article have been uploaded as part of the electronic supplementary material.

Author contributions

A.C.S. and H.D. conceived of the study and collected data. N.C., A.C.S., H.D. and E.A.C.T. designed and performed analyses, wrote the article and approved it for submission.

Competing interests

We have no competing interests.

Funding

E.A.C.T. received research support as a Bass University Fellow in Undergraduate Education at Stanford University. N.C. received research support from the Ruth Landes Memorial Research Fund and the Stanford Center for Computational, Evolutionary, and Human Genetics.