Sasha, It is good that you are trying to improve your pronunciation. Here are a couple of notes: When pronouncing plurals or the third person ending (s) in the present simple in English-- If the consonant preceding the 's' is voiced, 's' will sound as voiced 'z': chairs, machines, lives, tells If the consonant preceding the 's' is voiceless, 's' will sound as voiceless 's': cats, pipes, walks, makes Vowels are always voiced: zoo-zoos hoe--hoes see-sees The reason for this is quite simple. It is easier to pronounce two voiced sounds together and easier to pronounced two voiceless sounds together. So the rule to remember is. WHATEVER IS EASIER TO PRONOUNCE IS CORRECT. With past tense -ed: If -ed is preceded by a voiceless consonant sound (p, k, sh, etc.) -ed sounds as a voiceless 't'. Remember that the 'e' is silent. shipped packed If -ed is preceded by a voiced consonant sound (d, b, v, etc.) -ed sounds as a voiced 'd'. Remember that the 'e' is silent. kidded lived If -ed is preceded by a vowel sound (often 'ay') -ed sounds as a voiced 'd' because vowels are always voiced. Remember that the 'e' is silent. booed cried Exception: If -ed is preceded by 't' pronounce a voiced -id. In this case, the 'e' is pronounced. chatted After certain vowels it is relatively difficult to fully pronounce the "r". The British often reduce it to a glottal stop, which is the so-called British silent r. Americans and Canadians pronounce every "r". They accomplish this by the simple trick of adding a schwa (ə) when necessary. The extra sound makes it possible to pronounce the "r" wherever it occurs. British car ...... Ca----"r" glottal stop only American car.......Ca---- ər The American 'r' in this position is really a semi-vowel. As for your question about semi-vowels: it is much too complex a question to discuss here since so much depends on what vowel comes before the semi-vowel.

I agree with the other members - if you just want to improve your pronunciation and use of spoken English, then you are analysing this WAY too much. The extra problem is dividing spoken English into "British" and "American". It's not a clear-cut division, especially regarding R at the end of a syllable - regional accents come into play here. My advice is just listen to British media (if that's the way you wish to go) and copy what you can. You'll also get a clearer understanding of regional UK accents that way. Most importantly, relax when speaking. :)

What on earth is a semi-vowel? All the thins you mentioned here are called "consonants". The business with voiced and unvoiced consonants is not hard at. In fact, it is terribly easy to understand. Why are you making it difficult for yourself? /w/ can be at the end of a word. For further examples of what you are asking, just browse a dictionary. Both American and British phonemes are given in modern dictionaries.

I'm not really sure what you are asking but if you want to understand how to obtain a better pronunciation of English you should first decide what location/accent you want to copy such as English（British) accent or American accent. It's good that you are very engaged in knowing the technical aspects of English but in my personal opinion, it isn't necessary. I'm sure 95% of Americans don't know what a semi-vowel is.