CS460/626 : Natural Language CS460/626 : Natural Language
Processing/Speech, NLP and the Web
(Lecture 31 Inside and Outside probabilities;
(Lecture 31–Inside and Outside probabilities;
PCFG training; start of phonetics and phonology)
phonology)
Pushpak Bhattacharyya Pushpak Bhattacharyya
CSE Dept., IIT Bombay 29th M h 2011 29th March, 2011
PCFG i id d t id
PCFG: inside and outside probabilities
probabilities
Inside probability β
Sentence probability
Calculation of β
Outside probability α
Sentence probability
Calculation of α
PCFG Training
PCFG Training
EM Algorithm for training
Phonetics and Phonology
Phonetics and Phonology
Morphology to Phonology: an exercise
The plural morpheme:
-s:
/s/ (cats)
/z/ (dogs) /iz/ (bushes)
/iz/ (bushes)
Whi h d h ld h ?
Which sound should occur where?
Phonetics and Phonolog Phonetics and Phonology
Phonetics: The study of speech sounds
Articulatoryy
Acoustic
Auditory
Phonology: the structure and patterning of sounds
Phonetic Transcription:
A writing system for representing speech
A writing system for representing speech sounds
The need for phonetic transcription
Eccentricity of English Spelling
Put/Putt/
Car/Kite
Rough/Puff
Fish can be spelt ‘ghoeti’. How?
A language for talking about
other/newly discovered languages
New languages without a writing system are discovered often
Classification
Manner of articulation
Place of articulation
Place of articulation
Voicedness
Stops
/p/ - voiceless bilabial
/b/ - voiced bilabial
/b/ - voiced bilabial
/t/ - voiceless alveolar
/d/ d l l
/d/ - voiced alveolar
/k/ - voiceless velar
/g/ - voiced velar
Fricatives
/f/
/v/
/v/
/th/
/dh/
/dh/
/s/
/sh/
/zh/
/zh/
/h/
Affricates
/ch/
/jh/
/jh/
Nasals
/m/
/n/
/n/
/ng/
The plural sound
Cats, racks … /s/
dogs rags /z/
dogs, rags … /z/
Bushes, classes … /iz/
Hypotheses?
A kudo to each of you!
Kudos: pronounced with an
/s/
sound at the endthe end
Misinterpreted as a plural
One kudo many kudos
One kudo, many kudos
Pronunciation becomes kudo/z/!
