Post on 23-Feb-2016
description
CS460/626 : Natural Language Processing/Speech, NLP and the Web
(Lecture 31–Inside and Outside probabilities; PCFG training; start of phonetics and
phonology)
Pushpak BhattacharyyaCSE Dept., IIT Bombay
29th March, 2011
PCFG: inside and outside probabilities
Inside probability β
Sentence probability
Calculation of β
Outside probability α
Sentence probability
Calculation of α
PCFG Training
EM Algorithm for training
Phonetics and Phonology
Morphology to Phonology: an exercise The plural morpheme:
-s: /s/ (cats) /z/ (dogs) /iz/ (bushes)
Which sound should occur where?
Phonetics and Phonology Phonetics: The study of speech
sounds Articulatory Acoustic Auditory
Phonology: the structure and patterning of sounds
Phonetic Transcription: 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 Voicedness
Stops /p/ - voiceless bilabial /b/ - voiced bilabial /t/ - voiceless alveolar /d/ - voiced alveolar /k/ - voiceless velar /g/ - voiced velar
Fricatives /f/ /v/ /th/ /dh/ /s/ /sh/ /zh/ /h/
Affricates /ch/ /jh/
Nasals /m/ /n/ /ng/
The plural sound Cats, racks … /s/ dogs, rags … /z/ Bushes, classes … /iz/
Hypotheses?
A kudo to each of you! Kudos: pronounced with an /s/
sound at the end Misinterpreted as a plural
One kudo, many kudos Pronunciation becomes kudo/z/!