The development of English at overseas locations depended on the one hand on the speakers emigrating and the kinds of English they transported. On the other hand the nature of the conditions at the new locations played an essential role. The former colonies differ greatly in their size, climate, topography, economy and demography and these are factors which determined the characteristics of new forms of English there.

The discussion of Southern Hemisphere English touches on an issue which has been the subject of considerable debate among linguists in recent years, namely whether certain features in extraterritorial varieties represent shared innovations on all their parts or developments of a common historical input. A clear case to illuminate this discussion is presented by short front vowels in South African, Australian and New Zealand English. In all three major varieties of Southern Hemisphere English these vowels are raised when compared to varieties in North America (excluding the recent Northern Cities Shift, Labov 1994) and in Britain, e.g. bad [ɛ], bed [be˕d], bid [bi˗d] or [bəd] (South African and New Zealand English).

For South African English Branford (1994: 474-80) deals in detail with the raised realisations of front short vowels. He also points out (Branford 1994: 477) that the raising of the TRAP vowel is probably an inherited feature of early 19th century English and quotes Wyld (1956) who comments on this in RP. He also sees the raised vowel in the DRESS lexical set and the centralised realisation in the BIT set as having antecedents in British English at the time of the first wave of settlers to the Western and Eastern Cape regions of South Africa (after 1795 and in the 1820s respectively). He also sees the raised and somewhat rounded realisation of the BATH vowel as a parallel with colloquial forms of London speech (Branford 1994: 480). The common ground between scholars like Branford and Lass on the one hand and Gordon and Trudgill on the other is that the latter assume that the raising of short vowels was a propensity in the historical input, but not yet realised, this having taken place in New Zealand. This is tantamount to saying that the chain shift upwards of short vowels had already begun but not advanced very far. In Britain in the 20th century a reversal of the raising of the TRAP vowel had set in by the middle of the century Bauer (1985, 1994: 120f.), halting any incipient general shift upwards. Because of the split between southeastern British English and Southern Hemisphere English in the early 19th century the latter was free to continue a vowel shift on a trajectory which British English did not pursue.

The larger of the former colonies — United States, Canada, Australia and to a more limited extent South Africa — experienced internal migration after the transportation of English. Obviously, communication networks have been important for the spread of English at new locations. For later immigration to the United States and Canada the establishment of railway connections facilitated the push westwards of European immigrants in both countries.

The development of varieties in the Southern Hemisphere has provided linguists with situations in which the rise of new varieties can be studied more comprehensively than anywhere in the Northern Hemisphere. In particular the contrast between embryonic and focussed varieties can be illuminated by case studies from this area. English on the Falkland Islands (Sudbury 2004) and English on Tristan da Cunha (Schreier 2004) show how nascent varieties are possibly moving towards clearer profiles by the preference, reallocation or dropping of input variants. In this situation the construction of local identity can be assumed to occur. An issue among linguists in variety studies is whether this largely unconscious process, which involves a whole range of social variables of which language is only one, is an epiphenomenon of the choices speakers make for purely linguistic reasons or whether the achievement of this local identity is a goal which is unconsciously pursued by speakers.

Not all cases of embryonic varieties lead to focussing, however. The external circumstances may militate against this. For instance, on the Bonin/Ogasawara Islands in the western Pacific, English, which was in contact with many languages, would seem to be on the decline after the reversion of the islands, which had been under United States control since the Second World War, to Japan. Most of the younger generation are monolingual Japanese or use mainstream varieties of English (Long 1999: 278).

A situation which demands special attention in the context of transported dialects is that of language shift (Thomason 2001) where an entire community switches from an indigenous language or languages to English. The speed at which this takes place varies. What is linguistically significant is that the members of the community learn English in an environment of uncontrolled second language acquisition. This kind of context is the nearest to that of creolisation which one can see historically in the Caribbean among the West Africans taken to this region as slaves. The main difference is that in a situation of language shift there is still access to the indigenous language whereas with creolisation this is not the case, this in fact is a defining feature of the latter situation.

Varieties of English which have arisen from language shift situations have not been the object of very much investigation. Obviously native Americans or Australian aborgines who switch from their native languages to English are engaged in language shift, see Malcolm (2001) on Aboriginal English. The Lumbee Indians (Dannenberg and Wolfram 1998, 1999) are a special case as they are racially mixed and because it is unclear what language or languages were spoken originally (see Wolfram and Dannenberg 1999: 183f. for a summary of current views, see pp. 192-207 for grammatical features).

There are, however, more established cases of language shift which have been the object of much study. The first is Ireland, of course, which in the 800 years of English settlement has seen a switch from Irish to English (as has happened in the Scottish Highlands with Scottish Gaelic). The second is KwaZulu-Natal in South Africa where the Indian labourers, transported there in the second half of the 19th century, switched to English in the 20th century. As predicted by Thomason and Kaufman (1988) both Irish and South African Indian English show phonological and grammatical interference from the native languages of those involved in the shift. This particular situation has recently been labelled ‘imposition’ (Guy 1990), where in the establishment of a second language variety by speakers in a shift context, features of their first language are ‘imposed’ on the target language. At least the following two basic distinctions in shift scenarios can be made.

1. A population movement (immigration) takes place with a switch to the language of the host country within a generation or two (Indian immigrants to KwaZulu-Natal).
   
2. The target language is brought to a country by settlers and there is a gradual shift by the indigenous population to this imported language over many centuries. The likelihood of interference is greatest here as imperfect bilingualism lasts longest (Irish speakers shifting to English in Ireland).
   

Irregular variation in a language, such as that found with the verb be or the inflection of present-tense verbs in English, can often be the subject of reanalysis in overseas varieties. Two examples can be cited here to illustrate what is meant. The first concerns the inflection of auxiliary verbs. These, like all others, show -s only on the third person singular (in those varieties which do not show a manifestation of the so-called Northern Subject Rule, Ihalainen 1994). This inflection is unusual in that it is irregular across the present-tense paradigm and does not apply to other tenses. In certain forms of English, such as south-east Irish English, and by extension, forms of English on Newfoundland deriving from this source, the variation between inflection and its absence has been reanalysed as a function of the status of the verb in question. Auxiliary verbs do not show inflection, e.g. He have used all the money up, but lexical verbs do, e.g. He has a new job at the factory.

The variation is characteristic of overseas varieties of English, particularly in the Northern Hemisphere, for a discussion of Newfoundland English, see Clarke (1997). The distinction between lexical and auxiliary forms of the verb is not always crucial, however. In Appalachian English (Montgomery 1994, 1997b), and in the South in general, variation is found which goes back some considerable time (Ellis 1994) but here it is not determined by the status of the verb, but rather on the nature of the subject (noun or pronoun) and such factors are distance of the subject from the verb. This type of variation is known in the literature as ‘verbal concord’ and may well have it origin in the Northern Subject Rule, mentioned above.

At any one point in time a variety is likely to contain at least some elements which are afunctional (as a left-over from former historical stages, Lass 1990). A case which illustrates this is provided by English in the 17th and 18th centuries where the use of do as an emphatic in present-tense declarative sentences (as in I do like linguistics) was not yet definitely established, less in the west of England, which was a common source of settlers in Ireland, than in the east. Thus a syntactic structure was available in early modern Irish English which in itself was still in the process of becoming identified with a specific function. What would appear to have happened is that those Irish speakers who were in the process of transferring to English, through a process of untutored second language learning as adults, took the still afunctional do of declarative sentences and refunctionalised it as a means of expressing habitual aspect (Hickey 1997) as seen in sentences like They do be out fishing often or She does come over to our place after dark. The fact that the trade-off with such refunctionalisation was minimal, in terms of disruption of syntax, probably facilitated the process.

The term ‘founder principle’ was devised by Salikoko Mufwene in an article on creole genesis (see Mufwene 1996). The label is intended to highlight the fact that the early settlers at an overseas location set the scene for the later development of a variety. The number of early settlers is not the central issue, but the fact that they are the first to bring to the new language to a new location and it is their speech which is handed down to later generations. As a generalisation this is basically true, but there are a number of other factors to be taken into account when considering the formation of overseas varieties.

The early settlers may well have been mixed, so that it is the mixture which is important. The outcome of dialect mixing (Trudgill 2004, Hickey 2003) depends on the relative numbers of settlers, but also on the social standing of the different groups and such additional aspects such as whether they came as established families or young individuals who founded families at the new location. Furthermore, the geographical distribution at the new location is important: did settlers congregate, did they live in cities or in relatively isolated rural areas?

The ‘founder principle’ can only be taken to apply in those cases where there is unbroken continuity of native-speaker varieyties at a location. But this did not always hold: in some countries language shift took place, i.e. the indigenous population moved from their original native language to English, usually over a period of some centuries. In such instances, the shape of the variety may not have been fixed until quite late, i.e. until the majority of speakers had shifted to English. This is true for parts of the British Isles, above all north and north-west Scotland and Ireland. It also applied to the Indian population in South Africa and to the Aboriginal population in Australia and the Maori in New Zealand, to name just a few of the better known examples.