a speech sound produced by humans when the breath flows out through the mouth without being blocked by the teeth, tongue, or lips

A short vowel is a short sound as in the word "cup". 短元音是诸如 cup 一词中的短音。

A long vowel is a long sound as in the word "shoe". 长元音是诸如 shoe 一词中的长音。

a letter that represents a sound produced in this way

The vowels in English are a, e, i, o, and u. 英语中的元音字母是 a，e，i，o，u。