Complex encoding in word-final voiced and voiceless stops.

Area of Science:

• Phonetics
• Speech Perception
• Acoustic Phonetics

Background:

• The distinction between voiced and voiceless consonants is crucial for speech intelligibility.
• Vowel and closure duration are known phonetic cues that can signal this opposition.
• Investigating the role of these durational cues across different speech rates and positions is essential for understanding speech production and perception.

Purpose of the Study:

• To investigate the multifunctionality of vowel and closure duration as cues for the voiced-voiceless distinction.
• To determine if these durational cues are tempo-independent.
• To examine the influence of speech rate and phonetic context on the perception of the voiced-voiceless opposition.

Main Methods:

• Two experiments were conducted using the word pair 'bag'-'back'.
• Experiment I utilized synthetic speech stimuli presented at three simulated rates of speech.
• Experiment II employed manipulated natural speech stimuli at two rates, in sentence-medial and sentence-final positions.

Main Results:

• In Experiment I, the vowel/vowel + closure duration ratio was identified as a tempo-independent cue for the voiced-voiceless distinction.
• Experiment II confirmed these findings in the final position, although interactions between durational and non-durational cues were observed.
• A specific context effect was noted for stimuli in the sentence-medial position.

Conclusions:

• Vowel and closure duration function as reliable, tempo-independent acoustic cues for the voiced-voiceless contrast in word-final positions.
• The perception of this contrast can be influenced by speech rate and surrounding phonetic context.
• These findings contribute to the understanding of phonetic cue weighting in speech perception.