Variable robustness of nonstandard /r/ in English: evidence from accent disguise

Abstract

In forensic phonetics it is valuable to identify speech features which are robust, that is, show little variability for a given speaker. This study was prompted by a case in which threatening telephone calls with apparent accent disguise exhibited standard English /r/, while the interviewed suspect exhibited /r/ pronunciations of a type traditionally described as 'defective'. An experiment was conducted in which subjects with standard and nonstandard /r/ read sentences in their native accent and then in imitation of a different accent exhibiting standard /r/. Acoustic analysis and auditory assessment suggest that /r/ is nonstandard if its F3 is above about 2000 Hz for men and above about 2350 Hz for women. Of five subjects whose native /r/ was judged nonstandard, three were able to produce standard /r/ in the assumed accent. The results are discussed, including the possibility that degree of native nonstandardness in /r/ may be a predictor of ability to modify it.