2 kinds of sound change:

a. regular or systematic

b. "accidental" speech errors

WAYS SOUNDS CHANGE

1. Reduced vowels-->unstressed vowels SOMETIMES reduce to schwa or barred i

The a in about

The e (and i!) in synthesis

The i in decimal

The o in harmony

The u in medium

The y in syringe

http://en.wikipedia.org/wiki/Unstressed_vowel

The e in roses is a barred i

The a in Rosa's is a schwa

http://www.hi.is/~peturk/KENNSLA/02/TOP/stress1.html

Other sound changes:

2. Assimilation: two adjacent sounds become closer together. Example: the [p] and [b] in "cupboard" progressive and regressive assimilation

3. Dissimilation: the opposite of assimilation, two sounds move farther apart. Example, "February" "Febyuary".

4. Metathesis: two sounds switch places. Example: Old English "thridda" is Modern English "third". wednesday, comfortable

5. Liaison: the introduction of a sound between words. Examples: French "il y a" becomes "y a t-il" when inverted.

6. Elision: is the loss of unstressed sounds, Elision example: "American" /merken/ him /im/. library" is pronounced "libary"

7. Epenthesis: the introduction of a sound between others. Example: "fire" = /faiyer/. "sherbet" "sherbert"

8. Haplology: the loss of syllables because nearby syllables sound similar. Example: Old English "Anglaland" became Modern English "England", probably /probly/ library" is pronounced "libry" Haplology would reduce to *haplogy if it were a common word.

http://en.wikipedia.org/wiki/Sound_change