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Development of coarticulatory patterns in spontaneous speech. Melinda Fricke Keith Johnson University of California, Berkeley. Why study spontaneous speech?. Laboratory speech is not always natural… articulatory differences psycholinguistic/planning differences.
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Development of coarticulatory patternsin spontaneous speech Melinda Fricke Keith Johnson University of California, Berkeley
Why study spontaneous speech? • Laboratory speech is not always natural… • articulatory differences • psycholinguistic/planning differences (Zharkova, Hewlett, & Hardcastle, 2011)
Why study coarticulation? • Coarticulation reveals speech planning. • articulatory planning, motor control • psycholinguistic planning, higher level processes (Zharkova, Hewlett, & Hardcastle, 2011)
What is coarticulation? Coarticulation: when an articulatory target affects adjacent targets. Anticipatory: [s] in “seat” vs. [s] in “suit” Perseverative: [s] in “geese” vs. [s] in “goose”
Research questions • Can we use acoustic measures to detect fricative-vowel coarticulation in a corpus of spontaneous speech? If so… • which ones? • differences between anticipatory and perseverative coarticulation? • differences between adult and child articulatory patterns?
The Corpora • Buckeye Corpus of Conversational Speech (Pitt et al., 2007) • 40 adults (20 men/women), ~ 1 hour each • sociolinguistic interviews • Davis Corpus, CHILDES Database (Davis et al., 2002; MacWhinney, 2000) • 21 children, ~ 1 hour/week • spontaneous interactions with caregivers
Adult data • total # of tokens = 3794 front [i, ɪ, e, ɛ] round [u, ʊ, o] anticipatory 1362[si] 1535 [su] perseverative 618 [is] 279 [us] TOTAL 1980 1814
Child data • 11 children (5 boys) produced tokens of [s] in identifiable words • age range: 1;1 – 3;1 • total # tokens = 3035 • total # unique words = 425 • “this” (630), “yes” (179) • “juice” (139), “house” (53), “nose” (33) front [i, ɪ, e, ɛ] round [u, ʊ, o] anticipatory 615 [si]103 [su] perseverative 1801[is] 516 [us] TOTAL 2416619
Child data Token Contributions by Child each color = 1 child 13 18 23 28 33 age in months
Fricative measurements • adult spectra 0 – 8 kHz • child spectra 0 – 11 kHz • all fricatives hand labeled • measurements taken at 4 locations • 40 ms Hamming window centered at • 20%, 50%, 80% duration of fricative • 20 ms into vowel • today: high frequency centroid, amplitude ratio, kurtosis
High frequency centroid • Inversely correlated with length of front cavity. low value = longer front cavity = rounding + PoA • Weighted mean frequency above… • 2125 Hz (men) • 2500 Hz (women) • 3500 Hz (children) (McGowan & Nittrouer, 1988; Li, Edwards, & Beckman, 2007)
Statistical modeling • Linear mixed effects regression • random effects • speaker, word (for child data only) • fixed effects • measurement location (20% vs. 80%) • context (round vs. non-round vowel) • interaction term • Separate models for adults vs. children, and for perseverative vs. anticipatory coarticulation
High frequency centroid Adult High Frequency Centroids, Anticipatory Results: Adults, anticipatory intercept 3737 Hz main effect round vowel -31 Hz No effect of measurement location. • Adults begin anticipating an upcoming round vowel at fricative onset. non-round round 3800 i 3750 u 3700 80% 20% measurement location
High frequency centroid Adult High Frequency Centroids, Perseverative Results: Adults, perseverative intercept 3703 Hz main effect round vowel -45 Hz interaction 72 Hz location:round • Adults correct for perseverative lip rounding by the end of the fricative. non-round round 3800 3750 i 3700 u 80% 20% measurement location
Amplitude ratio • Related to tongue posture high ratio = palatal articulation • Find peak above F2 region… mean amplitude in 1000 Hz band around high frequency peak – mean amplitude in 1000 Hz F2 region find peak here
Amplitude ratio Adult Amplitude Ratios, Anticipatory Results: Adults, anticipatory intercept 15.1 main effects location -1.1 round vowel -1.0 • More palatal articulation at beginning of fricative, and in non-round context. non-round round 16 15 i 14 u 80% 20% measurement location
Amplitude ratio Adult Adult Amplitude Ratios, Perseverative Results: Adults, perseverative intercept 13.4 no significant main effects interaction 2.4 location:round • Adult /s/ more palatal by the end of /us/ sequence. non-round round 16 15 i 14 u 80% 20% measurement location
Kurtosis • Correlated with lip rounding high kurtosis = more peaked distribution = more lip rounding • Calculated following Forrest et al. (1988)
Kurtosis Adult Kurtosis, Anticipatory Results: Adults, anticipatory intercept 3.1 main effect round vowel 0.01 • Adults show early anticipatory lip rounding, lasting throughout the fricative. non-round round 3.3 3.2 i 3.1 u 80% 20% measurement location
Kurtosis Adult Kurtosis, Perseverative Results: Adults, perseverative intercept 3.1 main effect round vowel 0.05 interaction - .07 location:round • Lip rounding disappears by the end of the fricative. non-round round 3.3 3.2 u i 3.1 80% 20% measurement location
Summary: Adult results • Adults begin anticipating upcoming round vowel at fricative onset. • Perseverative coarticulation lasts into the beginning of the following fricative, but is greatly reduced by the end.
High frequency centroid Child High Frequency Centroids, Anticipatory Results: Children, anticipatory intercept 5697 Hz main effect round vowel -20 Hz • Children also begin anticipating round vowel at fricative onset, but to a lesser degree. • Preview: lack of effect on kurtosis may indicate this difference is due to PoA, not lip rounding. non-round round 5750 i 5700 u 5650 80% 20% measurement location
High frequency centroid Child High Frequency Centroids, Perseverative Results: Children, perseverative intercept 5693 Hz main effect location - 10 Hz round vowel - 20 Hz • Perseverative effet lasts throughout fricative. • Main effect of location < utterance final position of most fricatives? non-round round 5750 i 5700 u 5650 80% 20% measurement location
Amplitude ratio Child Amplitude Ratios, Anticipatory Results: Children, anticipatory intercept 3.63 no significant predictors non-round round 5 i 4 u 3 80% 20% measurement location
Amplitude ratio Child Amplitude Ratios, Perseverative Results: Children, perseverative intercept 3.31 main effect location - 1 • Main effect of measurement location < most fricatives being utterance final? non-round round 5 4 i u 3 80% 20% measurement location
Kurtosis Child Kurtosis, Anticipatory Results: Children, anticipatory intercept 1.81 no significant predictors • Much lower values than adults (intercept = 3.1) • Suggests lack of lip rounding: coarticulation observed in centroid data may have been related to PoA. non-round round 1.90 1.85 u 1.80 i 1.75 80% 20% measurement location
Kurtosis Child Kurtosis, Perseverative Results: Children, perseverative intercept 1.81 main effects location - .003 • Again, no significant difference due to round vowel context. non-round round 1.90 1.85 i 1.80 u 1.75 80% 20% measurement location
Summary: Child results • Evidence for only gross motor control: • overall flatter spectrum < lack of tongue groove • lack of change/compensation in perseverative data • little evidence for lip rounding: differences in centroid may have come from PoA • BUT children anticipate upcoming round vowels as early as fricative onset (even though the gestures used to produce both fricative and vowel are different from adults’) • Suggests children’s planning is similar to adults’, but they lack the motor control needed to produce adult-like articulation
Comparison with previous findings • Zharkova et al. (2011b) concluded children don’t have differential control of tongue tip vs. dorsum by 7;7 • Our data are consistent with this conclusion • Also consistent with Nittrouer’s (1995) conclusion that different types of gestures develop along different timescales • Most previous studies have not looked at the interaction between age group and direction of coarticulatory influence.
Conclusion • We identified several acoustic measures that reveal fricative-vowel coarticulation in spontaneous speech. • Similarities between adults and children: • planning • constraints on articulation • Difference: • Motor control necessary to compensate for constraints
Thank you! (especially to Barbara Davis and Brian MacWhinney for making the child data available, and to Vanessa Chew for help segmenting fricatives)
Future work • Investigating additional variables: • random effect for word, for adults • age effects, for children • individual variation • lexical predictors (word frequency, neighborhood density) • control for neighboring segments, speech rate • compare within- vs. across-word coarticulation
Examples of child speech Cameron, age 22 months Rebecca, age 17 months