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Phonetics COMD2338 Taylor Vowel production Introduction to sound waves.

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Presentation on theme: "Phonetics COMD2338 Taylor Vowel production Introduction to sound waves."— Presentation transcript:

1 Phonetics COMD2338 Taylor Vowel production Introduction to sound waves

2 How many vowel sounds are there in US English? Between 11 and 13, depending on your dialect Does not include diphthongs Ex: Beat, bit, bait, bet, bat, but, bother, boot, book, boat, bawdy, body

3 Describing vowels Difficult to use tongue position as a descriptor High-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

4 [i] [u] [o] [ɑ][ɑ] [æ] [ʌ][ʌ]

5 Sound waves: Why describe sounds in terms of their physical nature? Helps speech pathologists understand how sounds can be confused For vowels, in particular, articulatory gestures are not very good descriptions Recordings Speech synthesis

6 What is sound? Sound: a disturbance of (air) molecules by some kind of movement These disturbances are called sound waves Sound waves cause molecules to move back and forth, bumping into one another Eventually this disturbance travels to your ear, causing your ear drum to vibrate Your brain perceives this as sound

7 How do sound waves work? Sound waves can differ in pitch quality loudness They spread like ripples in a pond... Voiced sounds: large, regular pulses Voiceless sounds: smaller, irregular pulses

8 Speech sounds Speech sounds are created when a sound passes through the vocal tract This sound resonates at different frequencies The frequencies at which this sound resonates are called formants Linguists have two ways to visually represent speech sounds: waveforms and spectrograms

9 Terminology Frequency: how fast the sound wave travels Measured in terms of Hertz (cycles per second) Think in terms of pitch Amplitude: how big of a disturbance the wave makes Measured in terms of decibels Think in terms of loudness

10 Sound properties of vowels Complex acoustic structure Number of different frequencies simultaneously pitch (auditory property) fundamental frequency (acoustic measure) pulses/second: 100Hz = 100 pulses/second you can hear F0 by using creaky voice added frequencies from resonance you can hear these by whispering/whistling

11 Spectrograms A spectrogram is an illustration of time, frequency, and amplitude Time: horizontal axis Frequency: vertical axis Amplitude: how dark the bars are Each dark bar represents a vowel formant

12 How to describe English vowel sounds Parameters (in order) 1.Height 2.Frontness 3.Rounding 4.Tenseness (if applicable) Diphthongs Dialect issues

13 All vowels (canonical)

14 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.

15 Some vowel mnemonics English height (descending): front: 'green mints may melt fast' back: 'nude cooks wrote bawdy logs' English lip rounding: green vs nude mint vs cook may vs wrote melt vs bawdy

16 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

17 Moving from one V to another Involves changing the auditory quality of the vowel accomplished by moving the tongue and changing the shape of the chamber difficult to describe exactly how your tongue is moving may not move the same way twice does not move the same way in different contexts

18 Diphthongs The nucleus is usually (although not always) the first V of the pair [o ʊ ], [a ʊ ], [a ɪ ], [e ɪ ], [ ɔɪ ] The nucleus is more prominent than the off-glide or the on-glide Off/on-glide is often very short Exception: [ju] in English Sometimes transcribed as a glide (consonant)

19 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: [a ɪ ] or [a j ] pie, rye, lied [a ʊ ] or [a w ] cow, how, round [ ɔɪ ] or [ ɔ j ] boy, coin, boil [o ʊ ] or [o w ] cold [e ɪ ] or [e j ]say (also: [i j ], [u w ]) keel, mood

20 American English diphthongs [e ɪ ]bait, gate [a ɪ ]bite, kite [o ʊ ]boat, goat [ ɔɪ ] boy, coy [a ʊ ]pow, cow [ju]cute, use [u w ]boo [i j ]key

21 Regional dialects: some examples cot/caught final [ ɚ ] to [ə]; [a ɹ ] to [a]; [ ɔɹ ] to [ ɔ ] [a ɪ ] to [a] (monophthongization) guy [i]–[ ɪ ] rotation beat bit [æ] to [iə] candle

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