Examination of Consonantal Phonetic Coverage in Standard Reading Passages

Abstract

Purpose: To be effective for clinical and research purposes, materials for eliciting speech should have phonetic coverage of a language, which necessarily includes both phonemic coverage (including all phonemes) and allophonic coverage (including positional contexts). The purpose of this work was to quantify allophonic coverage in widely used standard passages. Method: A total of 466 allowable contexts for 24 consonants in English were determined by taking into account positional contexts in terms of word positions, lexical stress, and proximity to other phonemes. The Caterpillar, The Grandfather Passage , and The Rainbow Passage were analyzed with respect to their phonetic coverage of these allowable contexts. Results: The standard passages achieved phonemic coverage, but their phonetic coverage was minimal: 24.89% in The Caterpillar , 27.25% in The Grandfather Passage , and 35.84% in The Rainbow Passage . Conclusion: Our analysis of three standard passages suggests the need for new speech materials that provide not only phonemic but also allophonic coverage so that production and perception of consonants can be examined as a function of their positional contexts.