Ultrasound Tongue Imaging

Abstract

This chapter describes ultrasound equipment and analysis followed by an overview of the type of speech errors which can be viewed with Ultrasound Tongue Imaging (UTI). An understanding of ultrasound tongue shapes in typical speakers is required in order to interpret ultrasound images from clinical populations. Clinical phonetic applications of UTI broadly fall into four different types: Comparisons with typical speakers, identification of covert errors/supplementing phonetic transcription, identification of covert contrasts and quantifying change post-intervention. Studies comparing the speech of clinical populations to typical speakers using UTI are relatively sparse to date. An alternative approach to comparing clinical populations to typical speakers is to compare speakers with reduced intelligibility to speakers from the same clinical group with normalized speech. For example, Cleland et al. describe a case study of a child called Rachel with persistent velar fronting who produced oral stops using a variety of different tongue shapes which appeared random, rather than phonologically patterned.