1. CE 40763 Digital Signal Processing Fall 1992 Phonemes and Phonetics
Hossein Sameti
Department of Computer Engineering
Sharif University of Technology

2. Phonetics and Phonemics :
The principle goal of Phonetics is to provide an exact description of every known speech sound
Domain of phonetics is independent of any particular language
Phonemics is used for the study of speech sounds as they are perceived by speakers of a particular language

3. Phonetics : Articulatory phonetics Acoustic phonetics
How any given speech sound is produced, with particular emphasis on anatomical detail
Acoustic phonetics
The emphasis is on observable, measurable characteristics in the waveform of speech sounds
Provides theoretical and experimental background for speech recognition and synthesis by electronic hardware

4. Articulatory phonetics :
The first task of articulatory phonetics is to describe speech sounds in the terms of position of the vocal organs
Phonetic alphabet
Phoneticians have had to devise their own system of notation
IPA
ARPAbet

5. Excitation Of The Speech System
Phonation
Whispering
Frication
Compression
Vibration

6. Articulatory phonetics (consonants)
Consonants are easy to define in anatomical terms
Point of articulation is the location of the principal constriction in the vocal tract
Bilabial
Labiodental
Apicodental
Apicogingival
Apicoalveolar
Apicodomal
Laminoalveolar
Laminodomal
Centrodomal
Dorsovelar
Pharyngeal
Glottal

7. …Consonants:
Manner of articulation: the degree constriction at the point of articulation and the manner of release into the following sound
Plosive
Aspirated
Affricative
Fricative
Lateral
Semivowel
Nasal
Trill

8. …Consonants:
Voicing: this indicates the presence or absence of phonation
Voiced
Unvoiced

9. Articulatory phonetics (vowels):
Vowels: vowels are much less well defined than consonants, this because tongue typically never touches another organ and vowels described by
Tongue high or low
Tongue front or back
Lips rounded or unrounded
Nasalized or unnasalized
Diphthongs: combined two vowel sound in a single syllable by moving tongue from one position to another

10. Articulatory phonetics :
Coarticulation:
No speech sound is produced accurately in the context of other sound
Overlapping of phonetic features from phone to phone is termed coarticulation

11. Phonemics :
Phonetics is a view of speech sounds independent of the language
Phonemics is the view of speech sounds within a specific language
Phonemes
Phonetics: an individual sound is a phone
Phonemics: the smallest meaningful unit in a specific language is the phoneme

12. Phonemics (phonemes):
A phoneme is the smallest sound unit in a given language that is sufficient to differentiate one word from another
Example:
In English, Voicing is a feature which distinguishes between two phonemes
‘bug’ contrast with ‘buck’
In some contexts voicing is not phonemics in German
‘Tag’ can be pronounced either [ta:g] or [ta:k]

13. World’s languages tree (Oxford Encyclopedia)
800 million
SINO-TIBETAN
Burmese
Chinese
Thai
Tibetan …
1,500 million
INDO-EUROPEAN*
150 million
SEMITIC and Related
Arabic
Ethiopic
Hamitic
Hebrew …
150 million
BANTU and Related
Swahili
Zulu …
140 million
MALAY-POLYNESIAN
Hawaiian
Indonesian
Maori …
130 million
JAPANESE-KOREAN
100 million
URAL-ALTAIC
Finnish
Hungarian
Mongolian
Turkish …
45 million
SOUTH-ASIAN
Vietnamese
Khmer …
130 million
DRAVIDIAN
Malayalam, Tamil, Telugu …
10 million
LATIN-AMERICAN INDIAN
Quechua
Guarani
Arawak
Carib …
60,000
Eskimo-Aleut
10 million
NORTH-AMERICAN
INDIAN
Aztecan, Algonquin, Iroquoian,
Sioan, …

14. World’s languages tree (Cont’d )
Indo-Iranian
Afghan
Bengali
Hindi
Kurdish
Persian
Sanskrit
Singhalese
Urdu …
Germanic
Dutch, Flemish
English
German
Scandinavian
Danish
Icelandic
Norwegian
Swedish
Yiddish
Armenian
Albanian
Romance
Italian
French
Portuguese
Romanian
Spanish …
Hellenic
Greek
Celtic
Breton
Irish Gaelic
Welsh …
Slavic
Bulgarian
Czech
Macedonian
Polish
Russian
Serbo-Croatian
Slovak
Slovene
Ukrainian …
Baltic
Lithunian
Lettish

17. Phonemics (phonemes):
The largest number of phoneme known is 45 in Chipewyan, the smallest is 13 in Hawaiian
English has 31 to 64 and Persian has 29 to 45 phonemes, depending on how they are analyzed

18. Phonemics (Allophones):
A phoneme is actually a set of phonetically similar sound which are accepted by the speakers of the language as being the same sound. Members of the set are called allophones.
Example:
The /k/ in “kin” and “cup”.
The /k/ in “cope” and “scope”.

19. English Phonemes uw ux uh ah ax ah-h aa ao ae eh Vowels
ih ix ey iy ay ow aw oy er axr el
y r l el w
jh ch s z sh zh f v th dh
m n ng em en eng nx
b d g p t k dx q
bcl dcl gcl pcl tcl kcl
hv hh
Vowels
Semi-vowels
Fricatives
Nasals
Stops
Aspiration

23. Speech Sounds of American English
There are over 40 speech sounds in American English which can be organized by their basic manner of production
Manner Class Number
Vowels 18
Fricatives 8
Stops 6
Nasals 3
Semivowels 4
Affricates 2
Aspirant 1
Vowels, glides, and consonants differ in degree of constriction
Sonorant consonants have no pressure build up at constriction
Nasal consonants lower the velum allowing airflow in nasal cavity
Continuant consonants do not block airflow in oral cavity

24. Vowel Production No significant constriction in the vocal tract
Usually produced with periodic excitation
Acoustic characteristics depend on the position of the jaw, tongue, and lips

25. Vowels of American English
There are approximately 18 vowels in American English made up of monothongs, diphthongs, and reduced vowels (schwa’s)
They are often described by the articulatory features: High/Low, Front/Back, Retroflexed, Rounded, and Tense/Lax

26. Spectrograms of the Cardinal Vowels

27. Vowel Formant Averages
Vowels are often characterized by the lower three formants
High/Low is correlated with the first formant, F1
Front/Back is correlated with the second formant, F2
Retroflexion is marked by a low third formant, F3

28. Vowel Durations Each vowel has a different intrinsic duration
Schwa’s have distinctly shorter durations (50ms)
/I, ε, Λ, Ω/ are the shortest monothongs
Context can greatly influence vowel duration

29. Happy Little Vowel Chart

30. Fricative Production Turbulence produced at narrow constriction
Constriction position determines acoustic characteristics
Can be produced with periodic excitation

31. Fricatives of American English
There are 8 fricatives in American English
Four places of articulation: Labio-Dental (Labial), Interdental (Dental), Alveolar, and Palato-Alveolar (Palatal)
They are often described by the features Voiced/Unvoiced, or Strident/Non-Strident (constriction behind alveolar ridge)

32. Spectrograms of Unvoiced Fricatives

33. Fricative Energy
Strident fricatives tend to be stronger than non-strident fricatives.

34. Fricative Durations
Voiced fricatives tend to be shorter than unvoiced fricatives.

35. Examples of Fricative Voicing Contrast

36. Friendly Little Consonant Chart
"Somewhat more accurate, yet somewhat less useful."

37. What is this word?
facetious

38. Stop Production Complete closure in the vocal tract, pressure build up
Sudden release of the constriction, turbulence noise
Can have periodic excitation during closure

39. Stops of American English
There are 6 stop consonants in American English
Three places of articulation: Labial, Alveolar, and Velar
Each place of articulation has a voiced and unvoiced stop
Unvoiced stops are typically aspirated
Voiced stops usually exhibit a “voice-bar’’ during closure
Information about formant transitions and release useful for classification

40. Spectrograms of Unvoiced Stops

41. Examples of Stop Voicing Contrast

42. Singleton Stop Durations

43. Voicing Cues for Stops
There are many voicing cues for a stop.

44. /s/-Stop Durations
Unvoiced stops are unaspirated in /s/ stop sequences.

45. Examples of Front and Back Velars

46. What is this word?
pacific

47. Nasal Production
Velum lowering results in airflow through nasal cavity
Consonants produced with closure in oral cavity
Nasal murmurs have similar spectral characteristics

48. Nasal of American English
Three places of articulation: Labial, Alveolar, and Velar
Nasal consonants are always attached to a vowel, though can form an entire syllable in unstressed environments
/ng/ is always post-vocalic in English
Place identified by neighboring formant transitions

49. Spectrograms of Nasals

50. What is this word?
fisherman

51. Semivowel Production Constriction in vocal tract, no turbulence
Slower articulatory motion than other consonants
Laterals form complete closure with tongue tip, airflow via sides of constriction

52. Semivowels of American English
There are 4 semivowels in American English
Sometimes referred to as Liquids or Glides
Glides are a more extreme articulation of a corresponding vowel
Similar, though more extreme, formant positions
Generally weaker due to narrower constriction
Semivowels are always attached to a vowel, though /l/ can form an entire syllable in unstressed environments

53. Spectrograms of Semivowels

54. Acoustic Properties of Semivowels
/w/ and /l/ are the most confusable semivowels
/w/ is characterized by a very low F1, F2
Typically a rapid spectral falloff above F2
/l/ is characterized by a low F1 and F2
Often presence of high frequency energy
Postvocalic /l/ characterized by minimal spectral discontinuity, gradual motion of formants
/y/ is characterized by very low F1, very high F2
/y/ only occurs in a syllable onset position (i.e., pre-vocalic)
/r/ is characterized by a very low F3
Prevocalic F3 < medial F3 < postvocalic F3

55. What is this word?
normalize

56. Affricate Production There are two affricates in American English:
Alveolar-stop palatal-fricative pairs
Sudden release of the constriction, turbulence noise
Can have periodic excitation during closure

57. Aspirant Production
There is only one aspirant in American English: /h/ (e.g., “hat’’)
Produced by generating turbulence excitation at glottis
No constriction in the vocal tract, normal formant excitation
Sub-glottal coupling results in little energy in F1 region
Periodic excitation can be present in medial position

58. Spectrograms of Affricates and Aspirant

59. What is this word?
tragic

60. Phonotactic Constraints
Phonotactics is the study of allowable sound sequences
Analyses of word-initial and -final clusters reveal:
73 distinct initial clusters (about 10 “foreign” clusters)
208 distinct final clusters
Can be used to eliminate impossible phoneme sequences:
/tk/ can’t end a word, and
/kt/ can’t begin a word,
Therefore, */: : : t k t : : :/ is an impossible sequence

61. Word-Initial Consonants from MWP Dictionary

62. The Syllable Syllable structure captures many useful generalizations
Phoneme realization often depends on syllabification
Many phonological rules depend on syllable structure
Syllable structure is predicated on the notion of ranking the speech sounds in terms of their sonority values

63. Syllables and Sonority
Utterances can be divided into syllables
The number of syllables equals the number of sonority peaks
Within any syllable, there is a segment constituting a sonority peak that is preceded and/or followed by a sequence of segments with progressively decreasing sonority values

64. The Syllable Template Branches marked by ° are optional
Nucleus must contain a non-obstruent
Sonority decreases away from nucleus
Affix contains only coronals:
Only the last syllable in a word can have an affix
/sp/, /st/, and /sk/ are treated as single obstruents

65. Some Examples

66. Words Containing /r/ and /l/

67. Acoustic Realizations of /r/

68. Acoustic Realizations of /l/

69. Allophonic Variations at Syllable Boundaries