Acoustic Properties of -s Related Morphemes in English: A Methodological Reevaluation

Area of Science:

• Linguistics
• Phonetics
• Speech Science

Background:

• English -s suffixes (plural, possessive, third singular) can sound alike but may have different phonetic realizations.
• Previous research shows conflicting results regarding acoustic differences (duration, center of gravity) between morphemic and non-morphemic -s sounds.
• Methodological variations in studies contribute to the lack of consensus on -s allomorph phonetic properties.

Purpose of the Study:

• To investigate how acoustic noise duration and fricative center of gravity (CoG) vary for each English -s allomorph.
• To determine the influence of sentence position, morpheme type, and phoneme category ([s] vs. [z]) on -s allomorph duration and CoG.
• To resolve discrepancies in existing literature regarding the phonetic realization of English -s suffixes.

Main Methods:

• Nine participants read experimental sentences containing 80 controlled -s allomorphs.
• Stimuli were designed to control for coda complexity, word/sentence stress, verb transitivity, sentence length, and surrounding phonemes.
• A linear mixed model was used to analyze acoustic data for duration and CoG.

Main Results:

• Significant interactions were found between sentence position, morpheme type, and phoneme category for duration.
• Plural and third-person singular [z] allomorphs were significantly shorter than non-morphemic [z] in medial sentence positions.
• A sentence position effect was detected for CoG, with lower frequencies in the final position, but no differences between morphemic and non-morphemic uses.

Conclusions:

• The findings align with studies employing comprehensive control over sentence positions, morphemes, and phonemes.
• This research refines methodology by using controlled reading stimuli, offering applications for morphosyntax intervention.
• The controlled phonetic environment provides a basis for future research on the perception of -s allomorphs.