Phonemics and Phonetics
Some simple definitions:
Phoneme:	·	an ideal sound unit with a complete set of articulatory gestures.
	·	the basic theoretical unit for describing how speech conveys linguistic meaning.
	·	(For English, there are about 42 phonemes.)
	·	Types of phonemes: vowels, semivowels, dipthongs, and consonants.

Phonemics:	·	the study of abstract units and their relationships in a language

Phone:	·	the actual sounds that are produced in speaking (for example, "d" in letter pronounced "l e d er").

Phonetics:	·	the study of the actual sounds of the language

Allophones:	·	the collection of all minor variants of a given sound
		("t" in eight versus "t" in "top")
	·	Monophones, Biphones, Triphones - sequences of one, two, and three phones. Most often used to describe acoustic models.

Three branches of phonetics:
·	Articulatory phonetics: manner in which the speech sounds are produced by the articulators of the vocal system.
·	Acoustic phonetics: sounds of speech through the analysis of the speech waveform and spectrum
·	Auditory phonetics: studies the perceptual response to speech sounds as reflected in listener trials.

Issues:
·	Broad phonemic transcriptions vs. narrow phonetic transcriptions
Phonemic and Phonetic Transcription - Standards
Major governing bodies for phonetic alphabets:
	International Phonetic Alphabet (IPA) - over 100 years of history
	ARPAbet - developed in the late 1970's to support ARPA research
	TIMIT - TI/MIT variant of ARPAbet used for the TIMIT corpus
	Worldbet - developed recently by Jim Hieronymous (AT&T) to deal with multiple languages within a single ASCII system

Example:
The Vowel Space
Each fundamental speech sound can be categorized according to the position of the articulators. This is known as the study of Acoustic Phonetics.
Average Formant Frequency Locations
Rules Relating Formant Frequencies and Vocal-Tract Characteristics:
· Length Rule: The average frequencies of the vowel formants are inversely proportional to the length of the pharyngeal-oral tract
· F1 Rule - Oral Constriction: The frequency of F1 is lowered by any constriction in the front half of the oral section of the vocal tract.
· F1 Rule - Pharyngeal Constriction: The frequency of F1 is raised by constriction of the pharynx
· F2 Rule - Back Tongue Constriction: The frequency of F2 tends to be lowered by a back tongue constriction.
· F2 Rule - Front Tongue Constriction: The frequency of F2 is raised by a front tongue constriction.
· Lip-Rounding Rule: The frequencies of all formants are lowered by lip-rounding.
What About Bandwidth?
When We Put This All Together:
We Have An Acoustic Theory of Speech Production
Consonants Can Be Similarly Classified
We can characterize a vowel sound by the locations of the first and second spectral resonances, known as a formant frequencies:
Some voiced sounds, such as diphthongs, are transitional sounds that move from one vowel location to another.