Effects of utterance position on English speech timing

Area of Science:

• Phonetics
• Speech Science
• Acoustic Phonetics

Background:

• Understanding consonant and vowel duration is crucial for speech production and perception.
• Previous research has explored phonetic variations in American English, but positional effects require further investigation.

Purpose of the Study:

• To investigate the influence of utterance position on the duration of stop consonant closures (/p/ vs. /b/) and vowel intervals in American English.
• To determine how phonetic context affects the acoustic properties of speech sounds.

Main Methods:

• Eight native American English speakers produced disyllabic utterances ([bábe], [pápe]).
• Supraglottal pressure variations were measured using a thin intraoral tube to define closure intervals.
• Acoustic analysis focused on stop closure duration and vowel duration.

Main Results:

• Stop closure duration for /p/ was consistently longer than for /b/ in medial positions.
• In initial positions, /b/ closure lengthened more than /p/, resulting in no significant duration difference between the two consonants.
• Utterance-initial position did not affect vowel duration, but utterance-final position lengthened both unstressed and stressed vowels.

Conclusions:

• Utterance position significantly modulates the acoustic realization of stop consonants and vowels in American English.
• The observed durational differences highlight the dynamic nature of speech production and the interplay between segmental and positional factors.