L2 Speech and Rhythm Metrics

1. UCSD Phonetics Lab UCSD Phonetics Lab L2 Speech and Rhythm Metrics Naja Ferjan Tristie A. Ross Amalia Arvaniti University of California, San Diego

2. The Acquisition of Rhythm • Rhythm has been claimed to be one of the first aspects of language to be acquired by infants (e.g., Nazzi et al. 1998, Nazzi & Ramus 2003) • Acquiring L2 rhythm, however, can be problematic for many non-native speakers and can significantly contribute to the perception of foreign accent (e.g., Barry 2007) • Despite its importance, rhythm has been one of the least studied aspects of second language learning (but see Trouvain & Gut 2007)

3. Issues in Assessing L2 Rhythm • Attempts to study L2 speech are complicated because of the large number of parameters that can affect it, which include • General proficiency in L2(e.g., Piske et al. 2001) • Frequency of L2 use(e.g., Flege & Liu 2001) • Age of L2 acquisition (e.g., MacKey et al. 2001) • Affect and motivation (e.g., Moyer 1999) • Similarities and differences between L1 and L2(e.g., Best et al. 2001, Flege et al. 2003) • All of these factors can have an impact on L2 rhythm • Here we focus on the effect of L1 rhythm class on the rhythm of L2

4. Rhythmic Class and Quantification • Abercrombie (1967) proposed that all languages fall into either the “syllable-timed” or the “stress-timed” category • Recently, a number of rhythm-quantifying metrics have been proposed (Ramus et al. 1999, Grabe & Low 2002, White & Mattys 2007) • Metrics are loosely based on the idea of Dauer (1983, 1987) that rhythm depends on relative consonantal and vocalic variability • Stress-timed languages are said to show greater vocalic and consonantal variability than syllable-timed languages • In addition, in stress-timed languages vowels are said to take up a smaller percentage of the overall signal, while in syllable-timed languages the overall duration of vocalic and consonantal intervals is more even

5. Hypotheses • Speakers whose L1 and L2 fall into the same rhythmic class should produce speech with more L2-like rhythmic properties than those speakers whose L1 and L2 belong to different rhythmic categories • Differences should be greater in spontaneous than read speech

6. Methods: Materials & Speakers • Languages • CONTROL: Southern Californian English –Stress-timed (1 M, 2 F) • Standard Northern German –Stress-timed (1 M, 2 F ) • Standard Italian –Syllable-timed (3 F) • Standard Latin American Spanish –Syllable-timed (1 M, 2 F) • Standard Korean –Syllable-timed?(1 M, 2 F) • Speakers • 18-36 year olds, recruited from the UCSD community • L2 speakers’ arrival to the US: 3 years or less before the recording • L2 speakers’ age of initial formal study of English: 6-23 years of age • Materials (in L1 and L2) • 15 read sentences • Read running speech: The North Wind and the Sun • Spontaneous Speech: 1-2 minutes

7. Methods: Measurements • Measurements of consonantal and vocalic intervals were made on the basis of phonetic criteria • Phrase-final intervals were not excluded • Pauses (very frequent in our L2 data) were excluded from measurement • Glides were included in vocalic intervals, if they showed no evidence of frication; they were included in consonantal intervals, if there was evidence of frication

8. Methods: Quantitative Analysis • Metrics • %V, ΔC • nPVI, rPVI • VarcoV, VarcoC • Statistics • One-way between-subjects ANOVA with L1 as a categorical variable and metric scores for L2 as dependent variables • One-way between-subjects ANOVAs with LANGUAGE (L1 English, L2 English, Speakers’ L1) as a categorical variable and metric scores as dependent variables • p < 0.05 whenever a difference between scores is reported

9. Results: cross-linguistic comparison • The scores of the German, Italian, Spanish and Korean speakers of L2 English were compared to the scores of L1 English speakers • We expected that the scores of the German speakers would be closer to the English controls, while the scores of the Italian, Spanish and Korean speakers would be substantially different from them • None of the comparisons were statistically significant • One of the possible reasons could be the extreme variability of the L2 data both across and within each L1 group of speakers

10. Results: VarcoV & VarcoC • VarcoV and VarcoC have been used for research in L2 rhythm (White & Mattys 2007) • They are said to be the most appropriate metrics for L2 speech because they normalize for speaking rate which is very variable in L2

11. Results: L1 German - L2 English • The scores of each group of L2 speakers were compared to their L1 scores and the scores of the L1 English speakers • For German, these comparisons were not statistically significant except for %V • %V was higher in L1 English than in either L2 English or L1 German

12. Results: L1 Italian – L2 English • Comparisons of scores from L1 English, L2 English and L1 Italian were not statistically significant except for ΔC and nPVI • L2 English has higher ΔC (an index of consonantal variability) than L1 Italian • L2 English has higher nPVI (an index of vocalic variability) than L1 Italian

13. Results: L1 Korean – L2 English • Comparisons of scores from L1 English, L2 English and L1 Korean were not statistically significant except for ΔC and rPVI • Both scores suggest greater consonantal variability for L2 English than L1 Korean

14. Results: L1 Spanish – L2 English • Comparisons of scores from L1 English, L2 English and L1 Spanish were statistically significant for ΔC, VarcoC and rPVI • ΔC and rPVI suggest more consonantal variability for L2 English than L1 Spanish (but not L1 English) • VarcoC, however, suggests more variability for L1 English than L1 Spanish and L2 English (and no difference between these two)

15. Discussion i • The overall language scores do not show differences across languages, except perhaps some expected differences between L1 and L2 (as in the Italian and Korean data) • In particular, the scores show that L1 rhythm is not transferred to L2 production in a straightforward manner that rhythm metrics can measure • we expected that German speakers would adapt to the English timing easily, but their vocalic variability scores in L2 were practically identical to their L1 scores • we expected that speakers of Spanish and Korean would not adapt to English timing easily, but their L2 scores are not significantly different from L1 English • However, the Korean and Spanish results do not necessarily reflect a mastery of English rhythm; rather, it is likely that the high scores were due to the great inter-speaker variability in L2

16. Discussion ii • In addition, some of the differences we found in metric scores may not necessarily reflect the attempts of L2 speakers to emulate English rhythm, but rather • (a) specific strategies for coping with L2 production • (b) the transfer of L1 features unrelated to rhythm • For example, Korean and Spanish L2 speakers showed more consonantal variability in L2 than in L1 • For Korean speakers this was most probably due to the elongation of certain consonants at hesitation points • For Spanish speakers this was probably related to the transfer of intervocalic consonant lenition from Spanish to English

17. Conclusion • Our results suggest that the various rhythm metrics may not offer a good method for studying L2 rhythm • They (occasionally) yield contradictory results (cf. the Spanish data on consonantal variability) • They may yield the same result for entirely different reasons, thus obscuring timing differences among L2 speakers of different L1s (cf. the Spanish and Korean results on consonantal variability) • It is thus necessary to look for ways of examining L2 rhythm that take into account these differences instead of reducing them to a number

18. MERCI naja@ling.ucsd.edutross@ling.ucsd.eduamalia@ling.ucsd.edu

19. References i • Abercrombie, D. (1967) Elements of general phonetics. Chicago: Aldine. • Barry, W. (2007) Rhythm as an L2 problem: How prosodic is it? In J. Trouvain & U. Gut (eds), Non-Native Prosody: Phonetic Description and Teaching Practice, 97-120. Berlin: Mouton de Gruyter. • Best, C. T., McRoberts, G. W., Goodell, E. (2001) Discrimination of non-native consonant contrasts varying in perceptual assimilation to the listener’s native phonological system. Journal of the Acoustical Society of America 109 (2), 775-794. • Dauer, R. (1983) Stress-timing and syllable-timing reanalyzed. Journal of Phonetics, 11, 51-62. • Dauer, R. (1987) Phonetic and phonological components of language rhythm. Proceedings of the 11th international congress of phonetic sciences, 447-450. • Flege J.E., Schirru, C., MacKey, I. (2003) Interaction between the native and second language subsystems. Speech communication 40, 467-491 • Flege, J.E., Liu, S. (2001) The effect of experience on adults’ acquisition of a second language. Studies in second language acquisition. 23, 527-552 • Grabe, E., Low, E. L. (2002) Durational variability in speech and the rhythm class hypothesis. Papers in Laboratory Phonology 7, 515-546. Berlin: Mouton.

20. References ii • MacKey, I., Meador, D., Flege, J.E. (2001) The identification of English consonants by native speakers of Italian. Phonetica 58, 103-125 • Moyer, A. (1999) Ultimate attainment in L2 phonology. Studies in second language acquisition, 21, 81-108. • Nazzi, T. Bertoncini, J., Mehler, J. (1998) Language discrimination by newborns: toward an understanding of the role of rhythm.Journal of Experimental Psychology: Human perception and Performance, 24 (3), 756-766. • Nazzi, T. & Ramus, F. (2003) Perception and Acquisition of Linguistic Rhythm by Infants. Speech Communication, 41, 233-243. • Piske, T., MacKay, I. & Flege, J. E. (2001). Factors affecting degree of foreign accent in an L2: a review. Journal of Phonetics 29, 191-215. • Ramus, F., Nespor, M., Mehler, J. (1999) Correlates of linguistic rhythm in the speech signal. Cognition, 72, 1-28. • Trouvain, J. & Gut, U. (2007) Non-Native Prosody: Phonetic Description and Teaching Practice. Berlin: Mouton de Gruyter. • White, L., Mattys S. L. (2007) Calibrating rhythm: First and second language studies. Journal of Phonetics, 35, 501-522.