PHONETICS AND PHONOLOGY DEFINITION

from: http://meridaciudad.olx.com.ve/taller-de-fonetica-inglesa-iid-253726792

Phonetics and phonology are two branches of linguistics that deal primarily with the structure of human language sounds. Phonetics focuses on the physical manifestations of speech sounds and on theories of speech production and perception. Phonology is concerned with the systems of rules (or constraints) that determine how the sounds of a language combine and influence one another. 

   Most phonetic work falls into the sub-field of articulatory phonetics (the study of the human vocal tract, the International Phonetic Alphabet, and how to make and describe language sounds), but with recent advances in computers and the availability of good phonetics software, there has been a recent boom in acoustic research (the physical properties of sounds-wave forms, pitch, intensity, spectrograms). 

   Phonology cares about the entire sound system for a given language. The goal is to formulate a model/theory which explains not only the sound patterns found in a particular language, but the patterns found in all languages. Examples of questions which are interesting to phonologists are: How do sounds change due to the sounds around them? (For example, why does the plural of cat end with an 's'-sound, the plural of dog end with a 'z'-sound, and the plural of dish end in something sounding like 'iz'?) How do sounds combine in a particular language? (For example, English allows 't' and 'b' to be followed by 'l' - rattle, rabble, atlas, ablative - so why then does 'blick' sound like a possible word in English when 'tlick' does not?) 

From: http://www.lcs.pomona.edu/page15/page1/page1.html