1. The Role of F0 in the Perceived Accentedness of L2 Speech Mary Grantham O’Brien Stephen Winters GLAC-15, Banff, Alberta May 1, 2009

2. Thank you Roswita Dressler Annika Orich Valerie Haberl Robert MacDonald Silke Weber Andreas Berkefeld

3. Motivation What effect does non-native prosody have on the perceived accentedness and intelligibility of speech? Production studies: perceptual interference between L1 and L2 (Holm 2008; McAllister 1997). Possible to rate accentedness in unfamiliar foreign language (Major 2007) Perceptual studies: intelligibility, comprehensibility and accentedness (e.g., Munro et al. 2006; Kennedy & Trofimovich 2008)

4. Intelligibility of L2 speech “the extent to which a speaker’s utterance is actually understood” (Munro et al. 2006, p. 112) measured through listener transcriptions Accented speech more intelligible if listeners share L1 of speaker (Kennedy & Trofimovich 2008) Positively affected by intonation manipulation.

5. Role of intonation in perception of foreign accent Differs according to study and L1-L2 pairings Segments Duration

6. Cross-linguistic intonation Languages differ both in average pitch height and range of frequencies (e.g., Braun 1994; Ladd 1996) German vs. English intonation Greater pitch range in English than in German (Eckert & Laver 1994; Gibbon 1998; Mennen 2007) Bilingual intonation Bilinguals adjust intonation, depending on language being spoken (Mennen 2007)

7. The current study Transplantation of both native and non-native intonation patterns onto the segments of the other language. German and English speakers Q1: Does mapping non-native intonation onto native segments affect perceived accentedness and intelligibility? Q2: Does mapping native intonation onto non-native segments affect perceived accentedness and intelligibility? Also: listeners included L2 German learners at a variety of proficiency levels.

8. Methodology: Stimuli 24 German and English sentences 12 declarative 6 yes/no questions 6 WH-questions Produced by: L1 English/L2 German (female) speaker L1 German/L2 English (female) speaker

9. Stimulus Conversion German speaker prosody transplanted onto English speaker segments, and vice versa… for productions in both languages. PSOLA-based manipulation algorithm developed by Mareüil & Vieru-Dimulescu (2006) Pink noise added to all stimuli for intelligibility test. 0 dB SNR for English stimuli +5 dB SNR for German stimuli

10. Stimuli Samples Unedited English: Converted English: Unedited German: Converted German: ClearIn Noise

11. Methodology: Tasks 1.Intelligibility Listeners heard natural + converted sentences in noise Typed in answers to question “What did the speaker say?” 2.Accent rating Listeners heard natural + converted sentences in clear Rated accentedness on a scale from 0 to 6 (0 = “no accent”, 6 = “most accent”) Two counterbalanced blocks: German and English

12. Methodology: Listeners Subjects: 22 native listeners of Canadian English 14 males, 8 females Aged 20-25 (mean: 22 years) Beginning to advanced learners of German Levels A2-C1 on Common European Framework of Reference for Languages (mostly levels B1 and B2)

13. Results: Accentedness Figure 3

14. Results: Intelligibility Figure 4

15. Results: German Accent Ratings by Listener Group Figure 5

16. Results: German Intelligibility by Listener Group Figure 6

17. Results: Summary Accentedness: 1.F0 transplantation decreases perceived accentedness of natively produced sentences… 2.But does not improve perceived accentedness of non-natively produced sentences. Intelligibility: 1.English sentences more intelligible than German 2.English speaker more intelligible than German in both language conditions 3.F0 manipulation reduces intelligibility in all conditions

18. Results: Summary Low proficiency German learners based accent ratings more on prosodic features; High proficiency learners’ ratings based more on natural vs. manipulated.  More top-down processing in case of high proficiency learners?

19. Conclusions Prosodic characteristics do play a role in the perception of accentedness (or lack thereof). true for both L1 and L2 perception. L2 listeners better understood L2 speaker in adverse listening conditions. Note: “Interlanguage speech intelligibility benefit” (Bent & Bradlow, 2003) Note: PSOLA-based manipulation induced unnaturalness into speech stimuli. possible limitations of synthesis algorithm

20. Future research Possible control: compare manipulated sentences with manipulated sentences. Also: perception of naturally produced F0 contours in both conditions (by phonetically trained speaker) Other directions: test native listeners of German Test broader range of speakers Test speakers of other languages with clearer prosodic differences Pitch Accent languages (French, Japanese) Tone languages (Chinese)

22. Accent Rating Screen

23. Results: Naturalness