The diphthongs of formal Nigerian English: A preliminary acoustic analysis

Postcolonial varieties of English, used in countries such as Nigeria, India and Singapore, are subject to both local (“endonormative”) and external (“exonormative”) forces, the latter often in the form of British/American English. This gives rise to a stylistic continuum, where informal speech is more endonormatively oriented than formal/educated speech, which, nevertheless, is clearly distinguishable from British/American English. The formal end of the continuum is often regarded as the incipient local standard. Nigerian English (NigE) is the most widely spoken African variety of English, but empirical/quantitative descriptions are rare. In this pilot study, we present an acoustic analysis of eight phonological diphthongs produced in formal contexts by nine educated speakers of NigE with L1 Yoruba and drawn from the ICE Nigeria corpus. Results show that the NigE speakers produced more monophthongal realisations of English phonological diphthongs than speakers of British English (BrE) do, as measured by trajectory length in F1-F2 space. Phonetically, most of these vowels can be considered monophthongs. The results can be explained through two factors at work during the foundation phase of NigE: (1) historical L1 influence and (2) the native English input present in the country, which involved more monophthongal realisations of some phonological diphthongs than in present-day BrE.