Stop Place Contrasts before Liquids

1. Stop Place Contrasts before Liquids Edward Flemming MIT

2. Does phonology have a biological grounding? • Phonology is shaped by the nature of speech perception and speech production. • Speech production and speech perception depend on biological endowments. • A case study adopting this approach to the analysis of a phonological pattern: Restrictions on stop place contrasts before laterals.

3. Restrictions on coronal-lateral clusters • Many languages allow initial [pl, kl]/[bl, gl] clusters, but exclude [tl, dl] (Kawasaki 1982). • E.g. English, German, Norwegian, Thai, etc • English: • [b-g, p-k] contrast before [l], blue-glue, plan-clan • initial [dl-, tl-] are not possible.

4. Restrictions on coronal-lateral clusters • This is a result of a dispreference for coronal-dorsal stop contrasts before laterals (Flemming 1995). • Some languages reverse the English pattern, • [tl-, dl-] OK, but no *[kl-, gl-]. • e.g. Haroi and other Chamic languages (Mudhenk & Goschnick 1977), Katu dialects (Wallace 1969): • Some languages have free variation between coronal and velar stops before lateral (but contrast elsewhere), e.g. Bolton English (Shorrocks 1998), Mong Njua (Lyman 1974)

5. Restrictions on coronal-dorsal contrasts before [l] • Kawasaki (1982) hypothesizes that this dispreference is due to perceptual similarity of [dl-gl], [tl-kl]. • General hypothesis: There is a preference for perceptually distinct contrasts. • Before [l], contrasts between coronal & dorsal stops are not very distinct. Previous evidence: • Kawasaki (1982): Evidence from 1 speaker that formant transitions are very similar in [dl-, gl-]. • But bursts can be sufficient to distinguish stops.

6. Restrictions on coronal-dorsal contrasts before [l] • Further investigate Kawasaki’s hypothesis through acoustic analysis of American English (and Hebrew). • Hypothesis: English [dl-gl] and [tl-kl] contrasts would be less distinct than legal stop place contrasts (e.g. [bl-gl], before vowels). • How do we infer the expected realization of [dl-, tl-]? • Other stop-liquid clusters • Medial [-dl-, -tl-] clusters • [tl-, dl-] in languages that allow these clusters (e.g. Hebrew, Russian). • But NB languages that allow these contrasts may realize stop-liquid clusters in a different fashion, e.g. less gestural overlap. • Focus on voiced clusters (Am. English medial -tl- often realized as -ʔl-).

7. Materials • 6 near-minimal pairs for bl-gl, e.g. blow, glow • 9 triplets for [b, d, g], each preceding the same set of nine vowels. • Sentence frame ‘Say X to me’ • Presented twice in random order • 5 native speakers of American English, 4 female, 1 male. • 6 near-minimal pairs for medial -dl-gl-, e.g. Ridley, wrigley • Same frame, presented twice in random order • 3 native speakers of American English, all female

8. Cues to stop place contrasts • Prevocalic stops (e.g. Dorman et al 1977): • Release burst - transient + frication • Formant transitions • Examine similar cues in stops preceding [l]. formant transitions burst

9. Measurements Formants: • Measured F2 and F3 as soon as possible after the end of the burst. Burst: • Burst duration - from stop release to onset of first formant. • Shape of spectrum of first 6 ms of the burst.

10. Quantifying burst shape • Measured from smoothed spectra (Hanson & Stevens 2003) • Calculate a series of seven DFTs on 3 ms windows at 1 ms intervals. • Average these spectra.

11. Quantifying burst shape • Burst peak: frequency of the highest amplitude in the spectrum • Amid-Ahi (cf. Suchato et al 2005) • Amid = average amplitude from 1.25 kHz - 3 kHz • Ahi = average amplitude from 3.5 kHz - 8 kHz bl bursts mid high gl bursts

12. Stop-[l] clusters - formants • English stops are not well differentiated by formant transitions before [l]. • Medial [-dl-, -gl-] • Small differences in F2 onsets • -dl- seems to allow more coarticulatory influence of a preceding front vowel. • Initial [bl-, gl-] • No significant differences in formant onsets.

13. Stop-[l] clusters - formants • Stops are not well differentiated by formant transitions before [l]. • Similar results from a preliminary study of Hebrew initial [bl-, dl-, gl-], [pl-, tl-, kl-] clusters (3 speakers): • Stops appear to be overlapped with following lateral, so formants at onset are largely determined by [l]. • Effect is particularly striking for English [-dl-], since prevocalic [d] is usually characterized by relatively high F2 at release (~2100 Hz) • Possibly lateral release of [d] facilitates the low F2 onset (1311 Hz)

14. * * * Stop-l clusters - burst • Initial [bl-, gl-] clusters are distinguished by burst quality and duration. • [gl] is more compact than [bl]. • [gl] burst has a higher peak than [bl] burst. • [gl] has a longer burst than [bl]. * p < 0.01

15. Stop-l clusters - burst • Medial [-dl-, -gl-] are also differentiated by their bursts. • But the properties of [-dl-] bursts deviate substantially from prevocalic [d] bursts in the direction of [g]/[gl] bursts.

17. Lateral release • The properties of the [dl] burst are expected consequences of laterally releasing [d]. • Centrally released [d] burst has significant high frequency energy because it is filtered by the short cavity in front of the alveolar closure. • But with lateral release, the front cavity includes the side passages opened up by lowering the sides of the tongue, and thus is significantly longer. • Hence lower frequency peak, more compact burst shape.

18. Dispreference for [d-g] contrast before [l] • Stop-[l] clusters are distinguished by burst not formant transitions. • The [bl-gl] contrast is plausibly more distinct than [dl-gl] because the burst of laterally released [d] is compact like a velar burst. • Not clear what leads to a preference for the labial-coronal contrast in Chamic etc. • preference for homorganic clusters? bl- -gl- -dl-

19. Lateral release • Similarity between [dl] and [gl] appears to be a result of lateral release of [d]. • Lateral release may play a role in unusually low F2 onset in [dl]. • Lateral release results in non-canonical [d] burst. • So if [d] were not laterally released, [dl]-[gl] contrast should be more distinct.

20. Thanks to Patrick Jackson Jones

21. Stop-l clusters (Ba)gley (ba)dly

22. * * * br vs. dr vs. gr - Formants • Formant transitions distinguish [br, dr, gr]. * p < 0.01

23. * * * * * * * br vs. dr vs. gr - burst • burst distinguishes [br, dr, gr] * p < 0.05