A
phoneme is a unit of sound in spoken language--the smallest unit of sound. A phoneme is not always pronounced the same way, but the
allophones (variant pronunciations) are
heard as the same sound by native speakers.
For example: the T in "ton" and the D in "done" are very similar, yet we identify them as two different phonemes, resulting in "ton" and "done" being regarded as two different words.
On the other hand, the T in "ton" is not the same sound as the T in "stun." Hold a square of toilet paper in front of your mouth while you say these words and you'll see it flutter from the puff of air following the T in "ton," while there is no puff and no flutter in "stun." The T in "ton" is
aspirated, whereas the T in "stun" is not. Nonetheless, even though we all pronounce the words that way, none of us (except linguists or people who are familiar with certain other languages) are conscious of the difference in pronunciation.
In Chinese, an aspirated T and an unaspirated T are
two different phonemes. T'ing and
ting are two different words. (I'm using an obsolete romanization system because the apostrophe denotes aspiration.) Speakers of English don't even hear the difference, which makes their first few lessons in Chinese rather challenging. We have to hang the square of toilet paper in front of their mouths.
The way we describe this is to say that aspiration is
phonemic in Chinese, but not in English. In Chinese, aspiration changes one phoneme into another, but in English it does not; it only changes it into a different
allophone of the same phoneme, one that native speakers are not conscious of.
English has a large number of phonemes compared to most languages. I'm not going to look them up, but I think I can list them all.
The consonants are: P B T D K G ("hard" G) CH J SH ZH (as in "fusion") M N NG L R W Y. (Sometimes W and Y are called "semivowels.") Obviously English spelling is not very consistent, so in writing, these letters do not always have these sounds, but I hope you understand my list.
The vowels are harder to list because we have eleven vowel phonemes and only 5 vowel letters. And also because they don't have the same pronunciation in American English and British English. But here is a list of words containing the eleven unique vowel phonemes in American English:
Cot cut fade fed leak lick boat bought Luke look had.
We also, arguably, have a twelfth vowel phoneme, technically known as the
schwa, after the Hebrew name for the sound. It's the unstressed A in portable, E in labeling, I in maximum, O in bacon, U in forum--if you're talking fast and not trying to enunciate clearly.
Some odd situations arise with our vowel phonemes that aren't well covered by the rules of linguistics. In American English (but
not British, Australian, Indian or South African English), the words "liter" and "leader" are
homonyms, i.e., they are pronounced identically. This
intervocalic ("between vowels") T and D, which occur in a great many words, are compressed into a flap--the same sound as the letter R in Spanish, Russian, and many other languages. Nonetheless, when we hear those words, we unconsciously pick the correct meaning from context, and
hear the first sound as T and the second as D.
I hope that helps.
Enough for one day. I'll wait and see if anyone else wants to explain morphemes or graphemes.
