An acoustic phonetic analysis of Lewis Gaelic stop consonants

Claire Nance and Jane Stuart-SmithUniversity of Glasgow

c.nance.1@research.gla.ac.ukj.stuart-smith@englang.arts.gla.ac.uk

Overview

• Stops in Gaelic• Approaches• Research questions• Methods• Results• Conclusions

Stops in Gaelic

• Word initial /ph th kh/ and /p t k/

• Word medial and word final /hp ht hk/ and /p t k/ (Ladefoged et al. 1998)

• (Also palatalised vs. velarised distinction)

Initial stops

bog ‘soft’

pòg ‘a kiss’

VOTVOT Vowel voicingVowel voicing ClosureClosure

Vowel voicingVowel voicing ClosureClosure

VOT vs. Pre-aspiration

• ‘the interval between the release of the stop and the onset of glottal vibration, that is, voicing’ (Lisker and Abramson 1964:389)

• ‘delay in the offset of normal voicing’ (Laver 1994:150)

• Aspiration ≠ pre-aspiration (Silverman 2003)

Medial and final stops

smoc ‘smoke’

snog ‘nice’

Vowel voicingVowel voicing CloseClose

Pre-aspPre-asp

Vowel voicingVowel voicing ClosureClosure

Pre-aspiration zoom in

smoc ‘smoke’

Vowel voicingVowel voicing CloseClose

Pre-aspPre-asp

Pre-aspiration zoom in

smoc ‘smoke’

CloseCloseCloseClose

Pre-aspPre-aspBreathy VoiceBreathy Voice

Approaches

• Ladefoged et al. (1998)• Ní Chasaide (1985)• Sociophonetics and consonants (Foulkes and

Docherty 1999)

Research questions

• A more complete analysis than Ladefoged et al. (1998)

• Is this system undergoing apparent time change?

Methods

• Native speakers of Lewis Gaelic• 3 ‘older’ (45-55), 3 ‘younger’ (20-24)• Recording conditions• Word list data• 2257 tokens analysed• Non-parametric statistical tests

Measures: durational

• Initial: VOT, vowel• Medial: vowel, modal voice, pre-aspiration,

breathy voice, voiceless pre-aspiration, closure, VOT

• Final: vowel, modal voice, pre-aspiration, breathy voice, voiceless pre-aspiration, closure

a c a

Measures: durational

• Segmenting on the waveform in Praat

Modal voiceModal voiceVowelVowel

Pre-aspirationPre-aspirationBVBV NoiseNoise

Measures: dynamic noise-based

• Quantification of noisiness• Anticipatory and carry-over effects (Gobl and Ní

Chasaide 1999)• Adapted zero crossing rate (Gordeeva and Scobbie

2010)• Collaborating with Olga ogordeeva@gmail.com• Measure of noise from the glottis in periodic and

aperiodic sections• BV measures (HNR, spectral tilt, jitter shimmer)• Standard zero crossings (Bombien 2006)

• BP filtered at 5000Hz and 1.5 x F0• Effects of filtering (Gordeeva and Scobbie 2010:18)

• Perceptual superiority of this measure

BP ZCR

‘bus’ unfiltered

‘bus’ filtered

Applied to initial stops

càl ‘cabbage’

Results: durational

• VOT in initial stops• Effect of place of articulation (cf. Cho and

Ladefoged 1999)

n = 1285

Results: durational

• Vowel length – the action is in the aspirated series (cf. Kessinger and Blumstein 1997)

n = 642

Results: BP ZCR – Initial system

n = 270

Medial system

• Pre-aspiration longer in aspirated series• Some breathy voice in unaspirated• VOT ns.

n = 54

Medial system

• Vowel length (cf. Ní Chasaide 1985)

% duration of pre-aspiration word medial /ht/ according to vowel length

n = 36

Results: BP ZCR – Medial system

n = 180

Apparent time change

• VOT longer in aspirated series for younger speakers (aspirated series again)

n = 642

Results: BP ZCR – Initial change

n = 90

Speech rate

• Young people speak faster?• Effects on VOT (Allen et al. 2003, Pind 1995)• Ratios

VOTVOT VowelVowel

Pre-aspirationPre-aspirationVowelVowel

BurstBurst

Vowel Start

Vowel Start

Vowel end

Vowel end

ClosureClosure

Apparent time change

• Pre-aspiration shorter• Pre-aspiration different

% modal voice, breathy voice and voiceless pre-asp in word medial stops

n = 157

Results: BP ZCR – Medial change

n = 36

Summary of results

• YP longer VOT• YP shorter and different pre-aspiration• Benefits of a noise-based dynamic measure • Results suggest can separate phonemic

categories and age groups across the syllable

Conclusions: systems

• Support for Kessinger and Blumstein (1997): aspirated series show most variation

• Phonetically aspiration and pre-aspiration are not the same

• BUT aspiration functions as a system:– Vowel length– Change in younger speakers

Conclusions: apparent time change

• Pre-aspiration results:– Diachronic instability of pre-aspiration (Silverman

2003)– Influence of English? (Contact, obsolescence…)– Greying of phonemic categories due to lexical attrition

• VOT results:– Stops functioning as a system so somehow

compensating?

• Implications

References• Allen, J., Miller, L., and DeSteno, D., 2003. Individual talker differences in voice-onset-time. Journal of Acoustic

Society of America, 113:1, pp. 544-552• Bombien, L., 2006. Voicing alterations in Icelandic – a photoglottographic and acoustic investigation. In J.

Harrington, C. Mooshammer, F Kleber, eds., Arbeitsberichte de sInstituts fürPhonetik der Universität Kiel, 37, pp. 63-82. Kiel: Universität Kiel

• Cho, T., and Ladefoged, P., 1999. Variation and universals in VOT: evidence from 18 endangered languages. Journal of phonetics, 27, pp. 207-229

• Foulkes, P., and Docherty, G., 1999. Urban Voices. London: Arnold• Gobl, C., and Ní Chasaide, A., 1999. Voice source variation in the vowel as a function of consonantal

context. In W. J. Hardcastle and N. Hewlett, eds., Coarticulation. Cambridge: CUP. pp. 122-134• Gordeeva, O., and Scobbie, J., 2010. Preaspiration as a correlate of word-final voice in Scottish English fricatives. In

S. Fuchs, M. Toda, M. Zygis, eds., Turbulent sounds: an interdisciplinary guide. Berlin: Mouton de Gruyter• Ladefoged, P., Ladefoged, J., Turk, A., St. John, S., 1998. Phonetic structures of Scottish Gaelic. Journal of the

international phonetic association, 28, pp. 1-41• Kessinger, R., and Blumstein, S., 1997. Effects of speaking rate on voice-onset-time in Thai, French, and English.

Journal of Phonetics, 25:2, pp. 143-168• Laver, J., 1994. Principles of phonetics. Cambridge: Cambridge University Press• Lisker, L., 1957. Closure duration and the intervocalic voiced-voiceless distinction in English. Language, 33:1, pp.

42-49• Lisker, L., and Abramson, A., 1964. A cross-language study of voicing in initial stops: Acoustical measurements.

Word 20, pp. 384-422• Ní Chasaide, A., 1985. Preaspiration in phonological stop contrasts: an instrumental phonetic study. PhD thesis,

University of Bangor• Pind , J . 1995. Speaking rate , voice-onset time , and quantity: The search for higher-order invariants for two

Icelandic speech cues. Perception and Psychophysics, 57, pp. 291–304• Silverman, D., 2003. On the rarity of pre-aspirated stops. Journal of linguistics 39:3, pp. 575-598

Mòran taing

Claire Nance and Jane Stuart-Smith

c.nance.1@research.gla.ac.uk

j.stuart-smith@englang.arts.gla.ac.uk

University of Glasgow

A word on breathy voice

• Ní Chasaide (1985:139) sees BV as purely physiological

• Some evidence to support this: no place effect• Some against: YP have more in velars

Word initial apparent time change

• Comparison to Ladefoged et al. (1998)• Word initial /th/ and /t/

Word medial apparent time change

• Word medial /hk/, noise and VOT

Closure durations

• Closure durations (Lisker 1957)• Longer in aspirated series• We found significantly longer closure

durations for coronals and bilabials in the aspirated series