phonetics comd2338 taylor vowel production introduction to sound waves

Phonetics COMD2338Taylor

•Vowel production

•Introduction to sound waves

How many vowel sounds are there in US English?Between 11 and 13, depending on your

dialectDoes not include diphthongsEx: Beat, bit, bait, bet, bat, but, bother,

boot, book, boat, bawdy, body

Describing vowels

Difficult to use tongue position as a descriptorHigh-low/front-back should not be viewed as

absolute descriptions of tongue positions

Vowel chart reflects frequencies; i.e., how one vowel sounds relative to the others

No distinct boundaries between vowels

[i][u]

[o]

[ɑ][æ]

[ʌ]

http://www.uiowa.edu/~acadtech/phonetics/

Sound waves: Why describe sounds in terms of their physical nature?Helps speech pathologists understand

how sounds can be confusedFor vowels, in particular, articulatory

gestures are not very good descriptionsRecordingsSpeech synthesis

What is sound?

Sound: a disturbance of (air) molecules by some kind of movementThese disturbances are called sound wavesSound waves cause molecules to move back

and forth, bumping into one anotherEventually this disturbance travels to your ear,

causing your ear drum to vibrateYour brain perceives this as sound

How do sound waves work?

Sound waves can differ inpitchqualityloudness

They spread like ripples in a pond. . .Voiced sounds: large, regular pulsesVoiceless sounds: smaller, irregular

pulses

Speech sounds

Speech sounds are created when a sound passes through the vocal tractThis sound resonates at different frequenciesThe frequencies at which this sound resonates

are called formants

Linguists have two ways to visually represent speech sounds: waveforms and spectrograms

Terminology

Frequency: how fast the sound wave travelsMeasured in terms of Hertz (cycles per

second)Think in terms of pitch

Amplitude: how big of a disturbance the wave makesMeasured in terms of decibelsThink in terms of loudness

Sound properties of vowels

Complex acoustic structureNumber of different frequencies

simultaneouslypitch (auditory property)

fundamental frequency (acoustic measure)• pulses/second: 100Hz = 100 pulses/second

you can hear F0 by using creaky voice

added frequencies from resonanceyou can hear these by whispering/whistling

Spectrograms

A spectrogram is an illustration of time, frequency, and amplitudeTime: horizontal axisFrequency: vertical

axisAmplitude: how dark

the bars areEach dark bar

represents a vowel formant

How to describe English vowel soundsParameters (in order)

1. Height

2. Frontness

3. Rounding

4. Tenseness (if applicable)

DiphthongsDialect issues

All vowels (canonical)

AmEngl Vowel Chart (Canonical Placement)

beat [i] boot [u]

bit [ɪ] father [ɚ] book [ʊ]

bait [e] sofa [ə] boat [o]

bet [ɛ] but [ʌ] caught [ɔ]

bat [æ] father [a] cot [ɑ]

Beware: There is considerable variation in English.

Some vowel mnemonics

English height (descending):front: 'green mints may melt fast'back: 'nude cooks wrote bawdy logs'

English lip rounding:green vs nudemint vs cookmay vs wrotemelt vs bawdy

Central Vowels in English

[ə] and [ʌ] are both considered “mid central unrounded vowels”, and the tense/lax distinction is not applicable.

[ʌ] is used in stressed syllables and stressed one-syllable words:cup, rug, above

[ə] is used in unstressed syllables, unstressed one-syllable words like ‘the’ [ðə]: sofa, above, the house

Use [ɚ] for unstressed syllables ending in [ɹ]:father

Moving from one V to another

Involves changing the auditory quality of the vowelaccomplished by moving the tongue and

changing the shape of the chamberdifficult to describe exactly how your tongue is

movingmay not move the same way twicedoes not move the same way in different

contexts

Diphthongs

The nucleus is usually (although not always) the first V of the pair [oʊ], [aʊ], [aɪ], [eɪ], [ɔɪ]

The nucleus is more prominent than the off-glide or the on-glideOff/on-glide is often very short

Exception: [ju] in English

Sometimes transcribed as a glide (consonant)

Diphthongs

A diphthong is a combination of vowels. The tongue moves from one vowel position (i.e. “target”) to another.

The final segment of a diphthong is often written as an ‘off-glide’ approximant

English diphthongs:[aɪ] or [aj] pie, rye, lied[aʊ] or [aw] cow, how, round[ɔɪ] or [ɔj] boy, coin, boil[oʊ] or [ow] cold [eɪ] or [ej] say(also: [ij], [uw]) keel, mood

American English diphthongs

[eɪ] ‘bait’, ‘gate’[aɪ] ‘bite’, ‘kite’[oʊ]‘boat’, ‘goat’ [ɔɪ] ‘boy’, ‘coy’[aʊ]‘pow’, ‘cow’[ju] ‘cute’, ‘use’[uw] ‘boo’[ij] ‘key’

Regional dialects: some examples

‘cot/caught’final [ɚ] to [ə]; [aɹ] to [a]; [ɔɹ] to [ɔ][aɪ] to [a] (monophthongization)

‘guy’[i]–[ɪ] rotation ‘beat’ ‘bit’[æ] to [iə] ‘candle’