Author: Maya Dewhurst

Nasality variation in Greater Manchester

Maya Dewhurst, m.dewhurst1@lancaster.ac.uk

Introduction
“Nasal voice” has been shown to be a salient, indexical feature of speech (Bucholtz, 2010; Podesva et al., 2013)
Extensive methods for measuring nasalization via articulation and aerodynamics (e.g. velum tracing, Ohala 1971; Rothenberg mask, Rothenberg 1973)
Focus turning to acoustics (Carignan, 2021; Liu et al, 2019; Pruthi and Espy-Wilson, 2004); development needed in order to apply acoustic methods to spontaneous speech
How do speakers in Greater Manchester vary in their nasal productions?
How do acoustics perform as nasality predictors?

Method
Eight speakers from Greater Manchester aged 15-16 stratified by gender and class (and ethnicity)
Recorded using nasometry system built at Lancaster University
List of monosyllabic words containing canonically oral and nasalized vowels (CVC, CVN, NVN)
Forced alignment and manual correction
Nasalance (equation 1, below): proportional nasal amplitude, used as indirect measure of nasal airflow

(1)

References
Bucholtz, M. (2010). White Kids: Language, Race, and Styles of Youth Identity. Cambridge University Press. https://doi.org/10.1017/CBO9780511975776
Carignan, C. (2021). A practical method of estimating the time-varying degree of vowel nasalization from acoustic features. J. Acoust. Soc. Am., 149, 911–922. https://doi.org/10.1121/10.0002925
Liu, L., Hulden, M., & Scarborough, R. (2019). RNN Classification of English Vowels: Nasalized or Not. Proceedings of the Society for Computation in Linguistics, 2(1), 318–321. https://doi.org/10.7275/cnem-ab98
Ohala, J. J. (1971). Monitoring soft palate movements in speech. 1–11. https://linguistics.berkeley.edu/~ohala/papers/monit-whole.pdf
Podesva, R., Hilton, K., Moon, K., & Szakay, A. (2013). Nasality as non-aggressiveness: An articulatory sociophonetic study [Conference presentation]. NWAV 42, Pittsburgh, Pennsylvania, United States. https://stanford.edu/~podesva/documents/nwav2013-nasality-1up.pdf
Pruthi, T., & Espy-Wilson, C. Y. (2004). Acoustic parameters for automatic detection of nasal manner. Speech Communication, 43(3), 225–239. https://doi.org/10.1016/j.specom.2004.06.001
Rothenberg, M. (1973). A new inverse-filtering technique for deriving the glottal air flow waveform during voicing. The Journal of the Acoustical Society of America, 53(6), 1632–1645. https://doi.org/10.1121/1.1913513
Styler, W. (2017). On the acoustical features of vowel nasality in English and French. The Journal of the Acoustical Society of America, 142(4), 2469–2482. https://doi.org/10.1121/1.5008854
Trudgill, P. (1974). The Social Differentiation of English in Norwich. Cambridge University Press.

Figure 2: Nasalance rates across tokens in a) female and male speakers, b) middle class and working class speakers, c) black speakers and non-black speakers

Discussion
Middle class speakers show significantly higher nasalance values across all tokens than working class speakers — consistent with accounts of increased nasalisation in middle class populations (Trudgill, 1974)
Ethnicity effect unanticipated but consistent with US English findings of nasality indexing “hyperwhiteness” (Podesva et al., 2013) — expansion of dataset required
No apparent effect of gender

Future directions
Perception:
- addressing relationship between perception and production
- exploring indexical properties of Manchester nasality
Further developing acoustic methods in order to analyse sociolinguistic interview data

Figure 3: Nasality scores for individual speakers based on linear regression models using PCA values from 20 acoustic correlates and 13 MFCCs (method based on Carignan, 2021).

Challenges
Acoustic correlates of nasalisation are notoriously unreliable because of the complications caused by the introduction of the nasal cavity as an additional resonator
Lots of individual variation
Using one point of measurement per token results in poor model fits — tracking nasalisation across the vowel may improve this?
Additionally, certain acoustic correlates cannot be compared directly between speakers, rather the difference between tokens (e.g. CVC vs CVN; Styler, 2017)
Determining where denasality lies in acoustic space