Context effects in recognizing syllable-final /z/ and /s/ in different phrasal positions

Area of Science:

• Phonetics
• Speech Perception
• Acoustic Phonetics

Background:

• Phrase-final lengthening affects speech sound duration.
• Voicing distinctions in fricatives (/s/ vs. /z/) rely on temporal cues.
• Understanding context's role in speech perception is crucial.

Purpose of the Study:

• To investigate how phrase-final lengthening influences the temporal cues for voicing in syllable-final /s/ and /z/.
• To determine if listeners benefit from sentential context for recognizing voicing.
• To explore the interplay between speaking rate and phonetic context in speech recognition.

Main Methods:

• Discriminant analyses were used to identify acoustic correlates of voicing.
• Two perceptual experiments tested listener recognition of fricatives in and out of context.
• Acoustic measurements included vowel duration, frication duration, and voicing/frication overlap.

Main Results:

• A combination of acoustic features successfully distinguished voicing independently of phrase-final lengthening.
• Listeners showed improved recognition of /s/ and /z/ when syllables were in sentential context.
• The benefit of context was greatest for /s/ in phrase-final position and /z/ in phrase-internal position.

Conclusions:

• Sentential context enables listeners to adjust for phrase-final lengthening's effect on vowel duration.
• Listeners more accurately interpret temporal cues for voicing when speech is embedded in context.
• These findings highlight the significance of extended phonetic context for accurate speech recognition.