U has 3 sounds in English.
The most common is "uh" as in: but, jut, luck (this is rather like the "shwah" sound in English.
The next most common sound for U sounds like the word "you". The sound is demonstrated by the word use, mute, puke, reputation. (Here the U joints with the previous consonant.
The third most common sound for U sounds like U as in put.
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