Perceiving final voiceless stops without release: effects of preceding monophthongs versus nonmonophthongs

Prepausal postvocalic stops in English are reported to occur both with and without audible release bursts, more or less randomly, and this difference is said to be without distinctive function. However, there is evidence that an English final stop, absent its release, may be of reduced intelligibility, particularly as to its place of articulation. Without audible release a final stop's place is conveyed mainly, perhaps entirely, by frequency shifts in the vowel formants. Among the vowels of English some are diphthongal, a property also signaled by formant shifts. The question arises: Is the intelligibility of an unreleased stop significantly affected by the phonetic nature of the vowel? Perceptual testing of appropriately chosen nonsense monosyllables ending in [p(downward left crop mark ) t(downward left crop mark ) k(downward left crop mark )] indicates that these stops are generally somewhat less intelligible after diphthongs. However, not all three stops are affected equally, [k(downward left crop mark )] perception being especially reduced in this context.