This article presents an analysis of speech rhythm in Tongan English, an emergent variety spoken in the Kingdom of Tonga. The normalised Pairwise Variability Index (nPVI-V) is used to classify the variety and determine the social and stylistic constraints on variation in a corpus of conversational and reading passage data with 48 speakers. Findings reveal a greater tendency towards stress-timing in speakers of the emergent local elite, characterised by white-collar professions and high levels of education, and those with a high index of English use. Variation is discussed as a consequence of proficiency, language contact and L1 transfer. An acoustic analysis of vowels in unstressed syllables of eight speakers confirms that lack of vowel centralisation (higher F1) is an underlying linguistic mechanism leading to more syllable-timed speech. Stark interspeaker variation was identified, highlighting the need to proceed with caution when classifying L2 Englishes based on speech rhythm.

The study explores the effect of deviations from native speech rhythm and rate norms on the assessement of pronunciation mastery of a second language (L2) when the native language of the learner is either rhythmically similar to or different from the target language. Using the concatenative speech synthesis technique, different versions of the same sentence were created in order to produce segmentally and intonationally identical utterances that differed only in rhythmic patterns and/or speaking rate. Speech rhythm and tempo patterns modeled those from the speech of French or German native learners of English at different proficiency levels. Native British English speakers rated the original sentences and the synthesized utterances for accentedness. The analysis shows that (a) differences in speech rhythm and speaking tempo influence the perception of accentedness; (b) idiosyncratic differences in speech rhythm and speech rate are sufficient to differentiate between the proficiency levels of L2 learners; (c) the relative salience of rhythm and rate on perceived accentedness in L2 speech is modulated by the native language of the learners; and (d) intonation facilitates the perception of finer differences in speech rhythm between otherwise identical utterances. These results emphasize the importance of prosodic timing patterns for the perception of speech delivered by L2 learners.

Polysyllabic shortening is used to maintain stress-timed rhythm in English, but used negligibly in Spanish. It is unknown how polysyllabic shortening is influenced when individuals are exposed to one language that employs it and one that does not. We calculated polysyllabic shortening for 35 functionally monolingual English-speaking adults and 19 relatively balanced Spanish–English bilingual peers who repeated English and Spanish nonwords. Results showed that speech motor patterns learned early in life might be sufficient to block cross-linguistic transfer of polysyllabic shortening despite limited language proficiency, and bilingual speakers appear to signal membership in the majority language by increasing polysyllabic shortening.

Previous studies have showed that at age 3;0, monolingual children acquiring rhythmically different languages display distinct rhythmic patterns while the speech rhythm patterns of the languages of bilingual children are more similar. It is unclear whether the same observations can be found for younger children, at 2;6. This study compared five Cantonese–English simultaneous bilingual children with five monolingual children in each language using both rhythmic metrics and qualitative data on syllable structure complexity and lexical stress. Results show that while the speech rhythms of monolingual children are different at 2;6, the rhythmic patterns of bilingual children are less distinct.

This study investigates the acquisition of speech rhythm by Cantonese–English bilingual children and their age-matched monolingual peers. Languages can be classified in terms of rhythmic characteristics that define English as stress-timed and Cantonese as syllable-timed. Few studies have examined the concurrent acquisition of rhythmically different languages in bilingual children. This study uses data of six Cantonese–English bilingual children around age 3;0 and compares them with six monolingual children in each language using recently developed acoustic rhythmic metrics on consonantal, vocalic and syllabic intervals. Qualitative data on syllable structure complexity and vowel quality are also included. Results on syllable duration show that monolingual children display distinct rhythmic patterns while the differences between the two languages of the bilingual children are less distinct. Bilingual English has less durational variability than monolingual English. Bilingual children have a distinct phonological developmental trajectory from monolingual children, which is manifested in acquisition delay and is influenced by language dominance. This shows that the two phonologies interact at the prosodic level.