Ibibio is a Nigerian tone language, spoken in the south-east coastal region of Nigeria. Like most African languages, it is resource-limited. This presents a major challenge to conventional approaches to speech synthesis, which typically require the training of numerous predictive models of linguistic features such as the phoneme sequence (i.e., a pronunciation dictionary plus a letterto-sound model) and prosodic structure (e.g., a phrase break predictor). This training is invariably supervised, requiring a corpus of training data labelled with the linguistic feature to be predicted. In this paper, we investigate what can be achieved in the absence of many of these expensive resources, and also with a limited amount of speech recordings. We employ a statistical parametric method, because this has been found to offer good performance even on small corpora, and because it is able to directly learn the relationship between acoustics and whatever linguistic features are available, potentially We present an evaluation that compares systems that have access to varying degrees of linguistic structure. The simplest system only uses phonetic context (quinphones), and this is compared to systems with access to a richer set of context features, with or without tone marking. It is found that the use of tone marking contributes significantly to the quality of synthetic speech.Future work should therefore address the problem of tone assignment using a dictionary and the building of a prediction module for out-of-vocabulary words.

In this paper we discuss the procedural problems, issues and challenges involved in developing a generic speech synthesizer for African tone languages. We base our development methodology on the "MultiSyn" unitselection approach, supported by Festival Text-To-Speech (TTS) Toolkit for Ibibio, a Lower Cross subgroup of the (New) Benue-Congo language family widely spoken in the southeastern region of Nigeria. We present in a chronological order, the several levels of infrastructural and linguistic problems as well as challenges identified in the Local Language Speech Technology Initiative (LLSTI) during the development process (from the corpus preparation and refinement stage to the integration and synthesis stage). We provide solutions to most of these challenges and point to possible outlook for further refinement. The evaluation of the initial prototype shows that the synthesis system will be useful to non-literate communities and a wide spectrum of applications.

We review and elaborate an account of consonantal strength that is founded on the model of speech as a modulated carrier signal. The stronger the consonant, the greater the modulation. Unlike approaches based on sonority or articulatory aperture, the account offers a uniform definition of the phonetic effect lenition has on consonants: all types of lenition (such as debuccalisation, spirantisation, and vocalisation) reduce the extent to which a consonant modulates the carrier. To demonstrate the quantifiability of this account, we present an analysis of Ibibio, in which we investigate the effects of lenition on the amplitude, periodicity, and temporal properties of consonants. We propose a method for integrating these different acoustic dimensions within an overall measure of modulation size.Not only does the modulated-carrier account cover all the classically recognised lenition types, but it also encompasses loss of plosive release in final stops – which, although not traditionally classed as lenition, is clearly related to processes that are.

Ibibio is a Lower Cross (Delta Cross, Cross River, New Benue-Congo, Niger-Congo) language spoken mainly in Akwa Ibom State and in parts of Cross River State, both located in the southeastern part of Nigeria. The number of speakers is estimated at about four million (Essien 1991). Previous work on Ibibio phonetics includes Connell (1992, 1994, 1995) and Urua (1996/97, 2000, 2002). The variety presented here is spoken in Uruan area and Uyo, the capital city of Akwa Ibom State and the recording is that of the author, a female university teacher from Uruan.

This paper presents a study of segment length and its relationship to the syllable in Ibibio, a Lower Cross language spoken in Nigeria. Syllable structure processes such as consonant lengthening, lenition, vowel lengthening and truncation all occur to satisfy syllable weight requirements.