Context-dependent modelling of English vowels in Sepedi code-switched speech

Abstract

When modelling code-switched speech (utterances that contain a mixture of languages), the embedded language often contains phones not found in the matrix language. These are typically dealt with by either extending the phone set or mapping each phone to a matrix language counterpart. We use acoustic log likelihoods to assist us in identifying the optimal mapping strategy at a context-dependent level (that is, at triphone, rather than monophone level) and obtain new insights in the way English/Sepedi code-switched vowels are produced