The reasons for the occurrence of African forms different from Standard English are manifold and can basically be attributed to at least four factors as far as their origin is concerned. For EAfE today the role of distinctly different native speaker English (e.g. Scottish English or even Scots) may be neglected, hence the importance of three major factor groups or reasons.

(a) Influence of the learners’ mother tongue and other African languages

Since English is learnt as a second language in East Africa, it is likely that features and strategies from first language acquisition are transferred; negative transfer is usually called interference. This has long been seen as the basic cause for African variation in English, because it obviously influences the pronunciation, often distinctly. Since non-African mother-tongue speakers as role-models are rare nowadays, common deviations become institutionalized and give a specific stamp to African English in its various forms. The great fear in Africa is that when one generation of poorly-trained African teachers passes on their English to the next generation, mother-tongue interference could be cumulative so that, with time, English could deviate more and more from accepted norms (like the minimal five-vowel system in EAfE below). From today’s perspective, mother-tongue influence on African English seems to have been overestimated. Because English is for many Africans only one possible choice in their verbal repertoire, which will include more than one African language, it may be safer to assume the influence of a common substratum of the African languages known by the English user. Interestingly enough, some speakers of African English exhibit “interference features” although they do not derive from their mother tongues but from other languages used in the area. Furthermore, often several factors may converge.

(b) General language learning strategies

The influence of general psycholinguistic processes on a second language is very difficult to assess; it is only possible to compare input and output of the human brain and draw conclusions on cognitive processing. There is some evidence that language learners in general use simplification strategies at an early stage (it seem_ that …, where morphological simplification may be supported by pronunciation simplification of an alveolar in front of a dental fricative). Later they try to reproduce memorized phrases from the target language, irrespective of the linguistic and pragmatic context (his/her level best seems to occur more often in African than in European English). From a certain stage onwards learners enjoy complicating their language and even tend to exaggerate typically English features (he is living in Eldoret is an overgeneralization when temporary meaning is not implied; she ran fastly is a hypercorrect form, as unmarked adverbs are associated with broken English). When the learning process does not progress normally, certain developmental errors, which occur regularly in first and second language acquisition, become fossilized, i.e. they become permanent features (like the plural of non-count nouns like informations or discontents). This includes overgeneralizations like neglecting restrictions or differences between gerunds and infinitives in complementation (such as I wouldn’t mind to give instead of giving). All these creative strategies of language learners must have played a certain role in the development of African varieties of English.

(c) Exposure to the written language

The fact that in many societies, including African ones, the written word has an authority exceeding that of the spoken form has far-reaching consequences for English language learners, particularly in a situation where languages other than English dominate in oral communication. Thus African speakers of English tend to reproduce characteristics of written English even in the spoken form. Grammatical constructions and lexical items from relatively formal registers or spelling pronunciations, like [saɪd] or [ʤuɪs] for said and juice, will often be used. This explains the articulations of /h/ in heir or of /b/ in debt and generally the tendency of the central NURSE vowel to assume the sound value “suggested” by the orthographic symbol that represents it (e.g. [adZ] for urge vs. [he:d] for heard). As Shakespeare and the Bible have until recently – when they were replaced by modern African classics like Achebe and Meja Mwangi – been most commonly used for teaching the target language, African varieties have tended to have an archaic flavor.