What's the difference between "Y" and "I" in pinyin? What's the difference between "W" and "U"?

y. W is not an initial consonant, but a half initial consonant. When they appear alone, they need to be followed by I and U
i. U is the final
That is to say, if you pronounce y, you pronounce Yi and W, you pronounce Wu
So y and I, W and u sound the same
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Yi read "one" Wu read "Five"
Y and I have the same pronunciation, W and u have the same pronunciation