Week 5 - Vowels Mark Huckvale - University College London · diphthong. • The source-filter model...

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Week 5 - Vowels

Mark Huckvale

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Last Week

• Phonation is the main sound source in speech

• Phonation has a number of important linguistic and paralinguistic uses

• Modal voice is characterised by complete approximation, regular cycles, sharp closures

• Whisper, Breathy, Creaky and Falsetto voice can be contrasted with Modal voice

• Signal measures exist which can be used to characterise voice quality

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Phonology of English Vowels

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Speech Chain

Phonology

Phonetics Acoustics

Audition

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Short Long Diphthong

hid heed bade head hard bide had hoard buoyed hudd who’d beard hod heard bared hood hoe vanilla how

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Short Long Diphthong

hid ɪ heed iː bade eɪ head e hard ɑː bide aɪ had æ hoard ɔː buoyed ɔɪ hudd ʌ who’d uː beard ɪə hod ɒ heard ɜː bared eə hood ʊ hoe əʊ vanilla ə how aʊ

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STRUT FOOT

STRUT FOOT

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Vowel Articulation

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Close

Open

Front Back

i

e

æ ɑ

ɔ

u

Lip Rounding

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Vowel Quadrilateral

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Cardinal Vowel System

Daniel Jones (1881-1967)

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British English Monophthongs

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Acoustics of Vowel Production

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Larynx buzz

/iː/

/ɑː/

/uː/

Source-Filter Model

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Frequency response

Output spectrum ----------------------- Input spectrum

=

Output spectrum

Input spectrum

Frequency response

= x

vowel = source x filter

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The characteristic frequency response of an unobstructed vocal tract shows a small number of peaks caused by resonances of the tube. Phoneticians call these formants

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Frequency Frequency Frequency

Am

plit

ud

e

Res

po

nse

Am

plit

ud

e

Source Filter Vowel

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Frequency Frequency Frequency

Am

plit

ud

e

Res

po

nse

Am

plit

ud

e

Source Filter Vowel

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Frequency Frequency Frequency

Am

plit

ud

e

Res

po

nse

Am

plit

ud

e

Source Filter Vowel

F1 F2

The acoustic effects of the filter can be characterised by measuring the resonant frequencies of the first few formants (vocal tube resonances).

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Vowels on Spectrograms

[i] [ɑ] [u]

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Formant Space

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Vowel Formant Frequencies

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Vowel quadrilateral with one person’s formant frequencies superimposed

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Peterson & Barney, 1952

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British English Vowels

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Diphthongs

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British English Diphthongs

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Mechanical Speaking Machines

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Example Videos

• Martin Riches Talking Machine

• 3D printed vocal tract shapes

• Takanishi Lab at Waseda University

• Animatronic Tongue at Sheffield University

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Coursework

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Coursework

• Coursework counts for 25% of assessment for course

• The coursework is designed to assess how well you can write in a scientific manner about speech science.

• You will be assessed on the content, writing style and presentation of the coursework.

• An introduction to the articulation, phonology and acoustics of vowels at a level suitable for a new first year undergraduate to understand.

• Incorporate data from the lab session on vowels

• Hand in through Moodle in last week of term

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Summary

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Summary

• Vowels may be described in terms of phonology, phonetics, acoustics and audition.

• There are abut 20 phonological choices for vowels in English. • The Cardinal Vowel system can be used to describe the quality of

any vowel in any language. • Vowel quality can be described using terms such as front-back,

open-close, rounded-unrounded, short-long, monophthong-diphthong.

• The source-filter model of vowel production explains the acoustic form of vowels

• The frequency response of the vocal tract pipe used for vowels can be characterised using the frequencies of the first few formants.

• Formant frequencies for a given phonological vowel vary across speakers, even of the "same" articulation.

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Lab Session

• Measure the formant frequencies of your 4 “corner” vowels: /iː/, /æ/, /ɑː/ & /uː/

• Attempt to synthesize copies of your vowels using an articulatory synthesizer