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Positional Velar Fronting: An updated articulatory analysis. Tara McAllister Montclair State University, NJ April 10th, 2010. Acknowledgements . Adam Albright Edward Flemming Donca Steriade Yvan Rose Katherine Demuth Stefanie Shattuck-Hufnagel Magdi Sobeih Haiyan Su B and family.
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Positional Velar Fronting:An updated articulatory analysis Tara McAllister Montclair State University, NJ April 10th, 2010
Acknowledgements • Adam Albright • Edward Flemming • Donca Steriade • Yvan Rose • Katherine Demuth • Stefanie Shattuck-Hufnagel • Magdi Sobeih • Haiyan Su • B and family International Child Phonology Conference 2010
Positional velar fronting • Velar fronting is frequently observed to apply in word-initial/pretonic but not word-final/posttonic contexts (Ingram, 1974; Chiat, 1983; Stoel-Gammon, 1996; Bills & Golston, 2002; Morisette, Dinnsen, & Gierut, 2003; Inkelas & Rose, 2003, 2008). • Examples of positional velar fronting (PVF): Prosodically strong contexts Prosodically weak contexts International Child Phonology Conference 2010
Neutralization in strong position • Puzzling pattern in child phonology: Phonemic contrast can emerge in weak/final before strong/initial position (Buckley, 2003; Inkelas & Rose, 2003, 2008; Dinnsen & Farris-Trimble, 2008). • Reverses a strong generalization across adult phonologies: Phonemes with limited distribution occur in strong position only. • Has roots in perceptual asymmetry favoring initial/prevocalic over final/postvocalic contexts (Fujimura, Macchi, & Streeter, 1978). • Continuity problem: If we write formal constraints flexible enough to accommodate child patterns, we predict patterns that are unattested in adult phonological typology. International Child Phonology Conference 2010
Neutralization in strong position • Possible solution if we adopt a phonetically-based version of phonology(Hayes, Kirchner & Steriade, 2004): • We know that children and adults face significantly different phonetic pressures. • Perceptual sensitivity (Elliott & Hammer, 1988) • Articulatory anatomy (Crelin, 1987) • Speech-motor control abilities (Kent, 1992) • If children and adults are subject to different low-level phonetic pressures, their phonologies should look different as well. • Child-specific constraints become inactive as child-specific phonetic pressures are eliminated in normal maturation. International Child Phonology Conference 2010
Articulatory account of velar fronting:Inkelas & Rose (2003, 2008) • In adult speech, consonants in strong position are produced with larger, stronger gestures than in weak contexts (Fougeron & Keating, 1996). • Child perceives prosodically enhanced gesture in adult speech and tries to replicate it. • Constraints on child speech: Larger, more anteriorly placed tongue (Crelin, 1987); decreased motor control (Kent, 1992). • The child’s attempted velar closure extends into the alveolar region, creating a coronal release. • Phonetically-motivated process is then phonologized. International Child Phonology Conference 2010
Articulatory account of velar fronting • I take up Inkelas & Rose’s insight that velar fronting is driven by child-specific articulatory phonetic factors. • Two new views: • New case study data show that fronting can be conditioned by finer-grained differences than the strong-weak dichotomy. • Expanded role for child-specific limitations on speech-motor control is proposed. International Child Phonology Conference 2010
Case study • Subject B, 4 years, male, monolingual American English learner. • Receiving therapy for severe speech sound disorder. • Followed longitudinally in biweekly sessions from 3;9 to 4;5. • Patterns of neutralization in strong position: positional velar fronting, positional fricative gliding. • All words containing a target velar were isolated from the transcript of B’s speech therapy sessions. • Total N = 2,408 International Child Phonology Conference 2010
Data coding • Observed output categories: • *Segmented production was specifically linked to velar place; never observed for coronal place. International Child Phonology Conference 2010
Analysis • All targets were coded for five factors: • Prosodic context (strong vs weak); • Voicing (voiced versus voiceless target); • Vowel context (back vs nonback); • Harmony context (other velar present vs absent); • Time of elicitation (four estimated developmental stages). • Data were fitted to a five-predictor logistic model with faithful velar place as the dependent variable. • Tested partial significance of predictors with χ-square statistic. • All main terms were significant predictors of variance (p < .001). International Child Phonology Conference 2010
Results: Prosodic context • Main effect of prosodic context: Weak > strong (Fisher’s Exact p < .000). • Consistent with previous literature. * Bars show standard error. International Child Phonology Conference 2010
Results: Voicing • Main effect of voicing: Voiced target > Voiceless target (Fisher’s Exact p < .000). • New finding. • From 4;2 on, fully faithful voiced targets contrasted systematically with segmented voiceless targets. * Bars show standard error. International Child Phonology Conference 2010
Unifying the conditioning factors • One old question and two new ones: • Why are velars more accurate in weak than strong position? • Why are voiced velars more accurate than voiceless velars? • Why does “segmented production” precede fully faithful velar production? International Child Phonology Conference 2010
Unifying the conditioning factors • All of the contexts associated with greater accuracy have relatively lower level of gestural force. • Consonant gestures are more forceful in prosodically strong position (Browman & Goldstein, 1995; Fougeron & Keating, 1996). • Gestural force is greater in voiceless than voiced plosives (Wakumoto et al., 1998; Mooshammer et al., 2007). • Voiceless stops have greater airflow (McGlone and Shipp, 1972); more forceful gesture is needed to offset intraoral pressure/avoid spirantization • “Segmented” production: Valving at glottis limits intraoral pressure (Clements & Osu, 2002), allows lighter articulatory contact. International Child Phonology Conference 2010
Unifying the conditioning factors • How can we modify phonetically-influenced grammar to capture general conditioning by gestural strength? • Violable phonological constraint Move-As-Unit: “Achieve linguopalatal contact by moving the tongue-jaw complex.” • Three pieces to the proposal: • Why child speakers favor jaw-controlled movements. • How jaw-controlled movement drives fronting. • Why Move-As-Unit is sensitive to gradient differences in articulatory force. International Child Phonology Conference 2010
Speech-motor limitations • Child lacks skill to plan movements with a large number of degrees of freedom (Fletcher, 1992). • Tongue is motorically complex; imposes simultaneous "skeletal, movement, and shaping requirements" (Kent, 1992). • Jaw is motorically simple (bilaterally hinged joint) . • In early stages of development, tongue may ride passively on active jaw (MacNeilage & Davis, 1990). International Child Phonology Conference 2010
Undifferentiated gestures • Jaw-controlled movement is linked to an undifferentiated pattern of linguopalatal contact. • Undifferentiated gestures: Midsagittal linguopalatal contact spanning alveolar through velar regions (Gibbon, 1999). • Reflects inability to control discrete functional regions of the tongue. • Proposal: Fronted velars are not true coronals but undifferentiated lingual gestures. International Child Phonology Conference 2010
Role of gestural force • Recall tongue’s "skeletal, movement, and shaping requirements" • When low and close to the mandible, some of the tongue’s shaping needs are filled by the lower teeth. • For a higher target, shaping requirements must increasingly be filled by lingual musculature. • Multiplies complexity of motor task. • Increases predisposition to use a jaw-controlled gesture. • Magnitude of Move-As-Unit violation is proportional to height of articulatory target. International Child Phonology Conference 2010
Conclusions • Move-As-Unit makes it possible to model B’s output across prosodic and voicing contrasts in all documented stages of development. • When child-specific articulatory limitations cease to apply, the constraint will be eliminated from the grammar. • Goals: • Model other problematic child processes (especially neutralization in strong position) using phonetically-sensitive constraint Move-As-Unit. • Look for direct evidence of undifferentiated gestures in velar fronting. International Child Phonology Conference 2010
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