Post on 29-Nov-2014
description
Phonetics & PhonologyAn Introduction
Sarmad HussainCenter for Research in Urdu Language Processing, NUCES, Lahore, Pakistan sarmad.hussain@nu.edu.pk
www.PANL10n.net 2
Levels of Linguistic Analysis
PragmaticsSemantics
SyntaxMorphology
Phonology
Phonetics
www.PANL10n.net 3
Overview
Phonetics
Phonology
Computational Phonology
Phonetics
www.PANL10n.net 5
What is Phonetics ?
Study of human speech as a physical phenomenon
Articulation
Acoustics
Perception
www.PANL10n.net 6
Articulatory Phonetics
Study of how speech sounds are produced by human vocal apparatus
Anatomy of vocal organs
Air stream Mechanism
Voicing
Articulation
www.PANL10n.net 7
Anatomy of Vocal Organs
[2]
www.PANL10n.net 8
Air-stream Mechanisms
Pulmonic
Glottic
Velaric
www.PANL10n.net 9
Pulmonic Sounds
Air flow is directed outwards towards the oral
cavity
Pressure built by compression of lungs
English [p], [n], [s], [l], [e]
www.PANL10n.net 10
Glottic Egressive Sounds
Air flow is directed outwards towards the oral
cavity
Pressure built by pushing up closed glottis
Georgian [p’], [t’], [k’]
www.PANL10n.net 11
Glottic Ingressive Sounds
Air flow is directed inwards from the oral
cavity
Pressure reduced by pulling down closed
glottis
Hausa, Sindhi [ɓ,ɠ ]
www.PANL10n.net 12
Velaric Sounds
Air flow is directed inwards from the oral
cavity
Pressure reduced by forming velaric and
alveolar closure and pulling down tongue
clicks
www.PANL10n.net 13
Articulatory Phonetics
Study of how speech sounds are produced by human vocal apparatus
Anatomy of vocal organs
Air stream Mechanism
Voicing
Articulation
www.PANL10n.net 14
Bernoulli Effect
Air pumped from the lungs applies pressure on closed glottisHigh pressure opens vocal cordsHigh velocity air flow creates low pressure region pulling vocalcords together againProcess is repeated, producing vibrations in the vocal cords
[3]
www.PANL10n.net 15
Voicing
Whisper
Creak
bhBreathy Voice
phAspirated
bVoice
pVoicelessness
[4]
www.PANL10n.net 16
Articulation
Manners of Articulation
Places of Articulation
www.PANL10n.net 17
Consonants – Manners of Articulation
Lateral
Trill
Tap
mNasal
jApproximant
dʒtʃAffricate
Fricative
pStop
[4]
Flap
www.PANL10n.net 18
Places of Articulation
[2]
Labial
Alveolar
Dental
Labio-dental
PalatalVelar
Uvular
Pharyngeal
Laryngeal
www.PANL10n.net 19
Consonants – Places of Articulation
[9]
www.PANL10n.net 20
Consonants – Places of Articulation
Multiple Places of ArticulationGlottalPharyngealUvularVelar
dʒʃPalatalRetroflexAlveolarDentalLabio-dentalBilabial
[4]
www.PANL10n.net 21
Consonantal Sounds
[10]
www.PANL10n.net 22
Vowel – Features
Low / High
Back / Front
Round
Nasal
Long
www.PANL10n.net 23
Vowel – Minimal Pairs
Bag Big (English)/bæg/ /bɪg/Beat bit/bit/ /bɪt/Boot bait/but/ /bet/
www.PANL10n.net 24
/a/ Vocal Tract Outline
[11]
www.PANL10n.net 25
Vocalic Inventory
ɒɑaLow
ʌæHigher-low
ɔʌœƐLower-mid
ΩɚəEMean-mid
oɤø=öeHigher-mid
ʊƗɪLower-high
uɯɨ=ʉy=üiHigh
RoundedUnroundedRoundedUnroundedRoundedUnrounded
BackCentralFront
www.PANL10n.net 26
Vocalic Quadrilateral
[12]
www.PANL10n.net 27
Diphthongs
Combination of two vocalic sounds
English: [aj] I, eye [aj]
[aw] cow [kaw]
www.PANL10n.net 28
Gemination of Consonants
Double/long consonants
English: “misspell”, “unknown”
Urdu “ê 6”,“ 6”
www.PANL10n.net 29
What is Phonetics ?
Study of human speech as a physical phenomenon
Articulation
Acoustics
Perception
www.PANL10n.net 30
Periodic Sine Wave
PeriodTime to complete one cycle (sec)FrequencyNumber of cycles per second (Hertz)AmplitudeMaximum displacement of a periodic wave (dB)
www.PANL10n.net 31
Complex Periodic Waves
Sinewaves contain a single frequencyComplex waves contain multiple frequency waves added togetherComplex periodic waves contain only Sine waves at base (fundamental) frequency (F0) and integral multiples of F0 (Fourier’s Theorem)
F0
Ampl
itude
Time
www.PANL10n.net 32
Resonance
Response of a system is not constant for signals at all frequencies. The frequency which gives largest response is called Resonance (frequency).
F
www.PANL10n.net 33
Sound WaveSound waves are formed by longitudinal movement of particles creating high and low pressure regions called compressions and rarefactions
Graph of pressure at each point in time
1 2 3 4
www.PANL10n.net 34
Acoustic Phonetics
Source-Filter Model
Source
Filter
www.PANL10n.net 35
Source-Filter Theory: Filter
Response curve with tongue in neutral position Resonances are called Formants (F1, F2, F3, …)
[15]
F2
F3
F1
www.PANL10n.net 36
Source-Filter Theory: Source
Waveform and spectrum of the glottal pulse
[15]
Time
Ampl
itude
www.PANL10n.net 37
Source-Filter Theory
Combining the two results in results in spectrum of short vowel ‘ə’ (schwa)
www.PANL10n.net 38
Spectrogram
A spectrogram is a time-frequency-amplitude graph representing sound
“ a bab” “a dad” “a gag”
[16]
www.PANL10n.net 39
Spectrogram
[17] [16]
www.PANL10n.net 40
What is Phonetics ?
Study of human speech as a physical phenomenon
Articulation
Acoustics
Perception
www.PANL10n.net 41
Speech Perception
Acoustic signal is highly variable but perception is very stable (invariant)How do map physical variance to perceptual invariance?
Intrinsic vs. extrinsic normalizationCategorical perceptionArticulatory Invariance - recreation of articulatory gesturesAcoustic Invariance - stable regions in speech within articulatory variability…?
Phonology
www.PANL10n.net 43
What is Phonology?
Study of how sounds interact in various languages (phonetics conceptual representation)
Segmental phenomenaPhonemic Inventory and AllophonySound-change rules and ordering
Supra-segmental phenomenaSyllabificationProminenceTonesIntonation
www.PANL10n.net 44
Phoneme?
Mental concept representing a physical sound
Many to many mapping between phoneme and a phone within a language
English /t/ aspirated in “tunafish”
unaspirated in “starfish”
dental before labio-dental
flapped in “buttercup”
www.PANL10n.net 45
Phonological Features
Phoneme = set of features that are true at a given time for a particular phonemic unit (phonological features) (Auto-segmental theory)
Values of features can by unary or binary ( +/- for present/absent)
[18]
www.PANL10n.net 46
Phonological Features
Contrastive function: Each phoneme differs from others in at least one featureDescriptive function: Accurately describes phonetic nature of a sound (may include redundant, non-contrastive features)
Classificatory function: Explains and allows generalizations and common phonological processes
[18]
www.PANL10n.net 47
English Consonant Features
[18]
www.PANL10n.net 48
English Vowel Features
[18]
www.PANL10n.net 49
Phonological Rules
Humans are lazy so compromise articulation to reduce effortCompromise in Articulation changes the soundConstituents of a phonological rules are
Phonemes to be modified due to a ruleConditioning context in which the rule has to be firedChange that occurs in a sound after the rule has been fired
Rules are sometimes ordered in a language
www.PANL10n.net 50
Types of Phonological Rules
AssimilationAddition of features due to neighboring phonemes
n [+bilabial] / __ [+bilabial, +voiced, +stop]
DissimilationDeletion of features due to neighboring phonemes
[7]
www.PANL10n.net 51
Types of Phonological Rules
Insertion / DeletionAddition or deletion of an entire phone
MetathesisChange order of phonemes
prescribe => perscribeask => aks
[7]
www.PANL10n.net 52
Syllable
A syllable is a unit of sound composed ofA central peak of sonority (usually a vowel), and Consonants that cluster around this central peak
www.PANL10n.net 53
Syllable Structure
Syllable structure of Urdu word ن † /pɑkɪstɑn/
www.PANL10n.net 54
Syllabification
Syllabification is the process of dividing words into syllables
Nuclear ProjectionMaximal Onset PrincipleSonority Sequencing Principle
Template based MatchingTemplates: V, CV, CVC, CVCCDirection of largest template application: RTL, LTR
www.PANL10n.net 55
ProminenceSyllable(s) in a word may be more prominent than others Prominence can change meaning
Spanish: término, 'end' (noun), termíno, 'I'm finishing' terminó, 'she/he finished’
English‘ob.ject, ob.’ject‘con.tent, con.’tent
Syllable vs. stress timed languagesFinal heavy syllable is stressed, no secondary stress
Sensitive to segmental “quantity” or morasEvery odd syllable is stress, First has primary stress
www.PANL10n.net 56
Intonation
You are going!You are going.You are going?
Intonation carries linguistic meaning, e.g. emotion, intention, etc.Realized primarily through variation of F0 over a sentenceMultiple theories of how intonation is computed and realized, e.g. Pierrehumbert (TOBI), IPO, Fujisaki, etc.
www.PANL10n.net 57
Computational PhonologyLetter-to-sound rules (?)
Regular, heuristic, statisticalSound change rules
FSTRule base
Syllabification algorithmTemplate or sonority based algorithm
Stress-assignment algorithmStress-assignment algorithm
Intonation assignment algorithmRule-based algorithm – based on syntactic parse (?)Corpus based (Machine Learning) algorithmOther corpus based approaches
Thank you
www.PANL10n.net 59
References1. http://www.mapsofworld.com/world-language-map.htm2. http://www.ling.upenn.edu/courses/Spring_2001/ling001/phonetics.html3. http://www.umanitoba.ca/faculties/arts/linguistics/russell/138/sec5/phonatio
.htm4. http://web.uvic.ca/ling/resources/ipa/5. http://www.ling.mq.edu.au/speech/phonetics/phonetics/airstream_laryngeal
/vot.html6. http://www.indiana.edu/~hlw/PhonUnits/consonants2.html7. http://www.ling.ohio-state.edu/~xflu/201/phonology.pdf8. http://encyclopedia.thefreedictionary.com/IPA%20in%20Unicode9. http://www.ling.upenn.edu/courses/Summer_2003/ling001/lecture4.html
10. http://encyclopedia.thefreedictionary.com/International%20Phonetic%20Al
phabet
www.PANL10n.net 60
References11. http://www.haskins.yale.edu/Haskins/MISC/ASY/VOWELS/ah.html12. http://www.sil.org/mexico/ling/glosario/E005ei-VowelsChart.htm
13. http://people.deas.harvard.edu/~jones/cscie129/nu_lectures/lecture3%20/
formants1.gif14. http://www.umanitoba.ca/faculties/arts/linguistics/russell/138/sec4/formant
s.htm15. http://www.umanitoba.ca/faculties/arts/linguistics/russell/138/sec4/src-
filt.htm16. A Course in Phonetics by Peter Ladefoged
http://hctv.humnet.ucla.edu/departments/linguistics/VowelsandConsonants/course/contents.html
17. http://web.uvic.ca/ling/resources/ipa/18. Introduction to Phonetics and Phonology by Clark and Yallop
http://ifla.uni-stuttgart.de/~jilka/teaching/intro1/i3_features.pdf