When writing English we use the 26 letters of the alphabet. However, when speaking there are roughly 44 different sounds in English. These sounds are called phonemes. 英语文字由26个字母组成，不过英语语音却包含大约44个不同声音，这些声音被统称为音素。 If you're concentrating on the sounds of English, you need 44 characters to represent them all. One way of doing this is to use the 'phonemic alphabet', which has some extra characters to represent the sounds in English for which there is no clear equivalent letter or letters. 就英语语音而言，我们需要用44个不同的音标来表达全部音素，这就是英语语音字母表，其中包括元音和辅音。 | 
Unit One 一单元