Measures of speech rhythm and the role of corpus-based word frequency: a multifactorial comparison of Spanish(-English) speakers

Abstract

In this study, we address various measures that have been employed to distinguish between syllable and stress- timed languages. This study differs from all previous ones by (i) exploring and comparing multiple metrics within a quantitative and multifactorial perspective and by (ii) also documenting the impact of corpus-based word frequency. We begin with the basic distinctions of speech rhythms, dealing with the differences between syllable-timed languages and stress-timed languages and several methods that have been used to attempt to distinguish between the two. We then describe how these metrics were used in the current study comparing the speech rhythms of Mexican Spanish speakers and bilingual English/Spanish speakers (speakers born to Mexican parents in California). More specifically, we evaluate how well various metrics of vowel duration variability as well as the so far understudied factor of corpus-based frequency allow to classify speakers as monolingual or bilingual. A binary logistic regression identifies several main effects and interactions. Most importantly, our results call the utility of a particular rhythm metric, the PVI, into question and indicate that corpus data in the form of lemma frequencies interact with two metrics of durational variability, suggesting that durational variability metrics should ideally be studied in conjunction with corpus-based frequency data.

Prosody and its application to forensic linguistics

“…Meanwhile, in syllable-timed languages, syllable (and vowel) durations are theoretically more uniform within a phrase. Harris & Gries (2011) compare the vowel duration variability in the Spanish of bilingual Spanish-English speakers and monolingual Mexican Spanish speakers. This proves an interesting comparison, since the monolingual speakers speak a syllable-timed language, while the bilingual speakers also speak a stress-timed language; thus, this comparison affords a perspective of a prosodic system in bilingual speech.…”

“…This proves an interesting comparison, since the monolingual speakers speak a syllable-timed language, while the bilingual speakers also speak a stress-timed language; thus, this comparison affords a perspective of a prosodic system in bilingual speech. Harris & Gries (2011) hypothesize that bilingual speakers would exhibit a more stress-timed (or English-like) rhythm due to their bilingualism as compared to monolingual speakers. Furthermore, the metrics utilized also provide valuable insight into the way that speech rhythms and other suprasegmental features may be affected by differences in linguistic abilities; that is, prosodic features appear to vary depending on which of the two languages is dominant for any individual bilingual speaker.…”

“…Nazzi, Bertoncini, & Mehler 1998), suggesting that even newborns are sensitive to rhythmic typology. Furthermore, some prosodic elements do not appear to vary greatly after their acquisition, even if the speaker learns a second language: Harris & Gries (2011) show that vowel duration variability between monolingual Spanish speakers and bilingual Spanish-English speakers do not vary in high frequency words. Prosodic patterns also appear difficult to mimic: Wretling & Eriksson show that speech impersonators could alter spectral characteristics, but less so timing at the phoneme and word levels in imitating speech, suggesting that rhythm is somehow "hard coded" in the adult speaker (1998:1).…”

“…It then proceeds to describe Miglio, Gries, & Harris (2014), a comparison of prosodic coding of new information by bilingual Spanish-English speakers and monolingual Spanish speakers. A description of Harris & Gries (2011) follows. This study compares the vowel duration variability of bilingual Spanish-English speakers and monolingual Spanish speakers, and touches upon corpus-based frequency effects and differences in linguistic aptitude between the two speaker groups.…”

“…The first of these sections reviews Miglio, Gries, & Harris (2014) and will discuss intonation as it varies between monolingual Mexican Spanish speakers and bilingual American Spanish-English speakers, when used to mark new information in the speech signal. The second will describe portions of Harris & Gries (2011); specifically it will discuss how vowel duration variability differs in the Spanish of monolingual vs. bilingual speakers; it is generally accepted that vowel duration variability is related to differences in speech rhythms (as in Low & Grabe 1995), and it is thus related to the following, third section of this paper. The third section, in fact, will discuss a portion of Harris (in preparation), a study that uses a combination of prosody-based variables to distinguish between utterances of Spanish, English, and Portuguese sentences, even after the quality of these recordings has been so degraded as to make them indistinguishable (in terms of language) to a trained phonetician's ear.…”