Presentation on theme: "The Role of F0 in the Perceived Accentedness of L2 Speech Mary Grantham O’Brien Stephen Winters GLAC-15, Banff, Alberta May 1, 2009."— Presentation transcript:
The Role of F0 in the Perceived Accentedness of L2 Speech Mary Grantham O’Brien Stephen Winters GLAC-15, Banff, Alberta May 1, 2009
Thank you Roswita Dressler Annika Orich Valerie Haberl Robert MacDonald Silke Weber Andreas Berkefeld
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)
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.
Role of intonation in perception of foreign accent Differs according to study and L1-L2 pairings Segments Duration
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)
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.
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
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
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
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)
Results: German Accent Ratings by Listener Group Figure 5
Results: German Intelligibility by Listener Group Figure 6
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
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?
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
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)