Auditory and F-pattern variations in Australian okay: A forensic investigation

An understanding of the acoustic properties, as well as the nature of within- and between-speaker variation, of words which occur with high frequency in natural discourse, is of great importance in forensic phonetic analyses. One word which occurs with relatively high frequency in natural discourse, including telephone conversations, which are often a source of data in forensic comparisons, is okay. This paper presents the initial findings of a study of auditory and F-pattern variations in okay in a natural telephone conversation spoken by six male speakers of general Australian English. Seven pre-defined sampling points are measured within each token to determine the most efficient sampling points and formants for distinguishing between-speaker variation from within-speaker-variation in okay. F-ratios at these seven sampling points are calculated as a mean of ratios of between-to within-speaker variation. The greatest F-ratio is shown to be for F₄ at voice onset of the second vowel. Forensic implications are discussed.