/s/-stop Blends: Phonetically Consistent Minimal Pairs for Easier Elicitation Eric Reid, M.S., CCC-SLP Workshop Number PS 5 CSHA 2016 Annual Convention and Exhibition
/s/ + Kate = skate OR /s/ + gate = skate Disclosure: Financial No relevant financial relationship exists. Nonfinancial No relevant nonfinancial relationship exists.
Purpose of this session: To illustrate the similarity between /s/-stop blends and voiced plosive singletons, i.e. /s/ + gate = skate To offer suggestions for the practical application of this somewhat counterintuitive relationship A little review When two phonemes differ by only one feature, they are in minimal opposition to each other. Minimal pairs (word pairs in minimal opposition) have been shown to be useful in the treatment of certain phonological disorders (Baker & McLeod 2004). There are 3 pairs of stop consonants in English that vary ONLY by voicing (p-b, t-d, & k-g). The primary difference between the voiced and voiceless stops in prevocalic (word initial) contexts is the amount of time between the release of the stop and the beginning of vocal fold vibration (Lisker & Abrahmson 1964). Aspiration, a secondary consideration, is the puff of air emitted as a voiceless stop is released. Aspiration is not usually present in voiced stops (Klatt, 1975). VOICELESS long VOT, aspirated pear pie pay tie tan tip Kate caught cap VOICED short VOT, unaspirated bear buy bay dye Dan dip gate got gap What s different about /s/-stop blends When /s/ precedes one of the voiceless stops, VOT is shortened significantly, and the stop is deaspirated. The shortened VOT and the deaspiration of skill cause it to resemble gill more so than kill. Consider the spectrograms below.
gill skill kill do stew to bot spot pot Perceptual findings support acoustic predictions. If one were to record a word with an /s/-stop blend and digitally remove the /s/, the remaining plosive will likely be perceived as voiced. CMSD graduate students at Loma Linda University are tasked with performing this operation during a course in instrumentation, and they consistently report hearing the voiced plosive, i.e. skate - /s/ = gate.
Implications True minimal pairs result from contrasting /s/-stop blends with voiced singletons (see appendix for examples) Both IPA transcription and English spelling conventions draw attention away from the phonetic similarity of pairs like sky-guy. Pairing /s/-stop blends with voiceless stops (skate-kate) requires clients to both deaspirate the plosive and shorten VOT. Both SLP and client are predictably blind to these added operations. Pairing /s/-stop blends with voiced stop singletons removes an unnecessarily complex transformation and better focuses treatment on the target skill - blending from /s/. A therapeutic rationale that does not consider the principles under discussion may lead the therapist to miscue client. References: Baker, E. & Mcleod, S. (2004). Evidence-based management of phonological impairment in children. Child Language Teaching and Therapy, 20(3), 261-285. Klatt, D. (1975). Voice onset time, frication, and aspiration in word-initial consonant clusters. Journal of Speech and Hearing Research, 18, 686-706. Lisker L. & Abramson A. (1964). A cross-language study of voicing in stops: Acoustical measurements. Word, 20, 384 422.
deep steep ding sting ditch stitch day stay DO do stew door store doc stock dump stump
die sty doubt stout gill skill gate skate gab scab ghoul school got Scott guy sky
gum scum bead speed bit spit base space bed sped ban span boon spoon bore spore
bot spot bye spy boil spoil bun spun brr spur ST deep steep ding sting ditch stitch day stay do stew door store dock stock dump stump die sty doubt stout SK gill skill gate skate gab scab ghoul school got Scott guy sky gum scum SP bead speed bit spit base space bed sped ban span boon spoon bore spore bot spot bye spy boil spoil bun spun brrr spur These pages are reproducible. 2015, Eric Reid ereid@llu.edu