The unique finals are to simplify the exceptions we have discussed in advanced tips 2.1 and 2.2. Therefore you must finish those lessons first to understand those exceptions.

In Advanced tip 2.1, the exception is about to add w and y in the Initials, but they will not change the sounds.

In Advanced tip 2.2, the exception about -i (before),  -i (after) and ê , the rarely used phonetic; the linguist knows precisely why such complicated specification is needed, but it is a waste of time and effort for the general public, especially the elementary students. Therefore we have unique finals, and what you have to know is how they sound, no need to understand why they sound like that.

For example

zhi is not zh combined with i; it has its sound.

yuan is not y and uan; it has its sound.

Therefore in reading pinyin, Unique Finals come first; as long as it is one of these 16 unique pinyin, you can ignore its sound in a breakdown manner.

The 16 unique finals can be divided into five situations:

1. zhi, chi, shi, ri: The final i of these four syllables is not the usual final i (衣), but the vowel -i (the international phonetic symbol is [ʅ ]), basically it is an extension of the initials and would not involve the i (衣) . The pronunciation can be understood by the practice of sounding those words and to feel the position of the tip of the tongue when the prolonged sound of zhi, chi, shi, ri (知、吃、湿、日).

2. zi, ci, si: The final i of these three syllables is not the usual final i (衣), but the vowel-i (the international phonetic alphabet [ɿ]); basically It is an extension and then a sudden stop of the initials and would not involve the i (衣) . Pronunciation is that you can experience from the practice of zi, ci, si (兹、此、斯).

3. ye: (叶) This syllable is used when finals ie have no initial. It is composed of the initials y and the finals ê. Same as any other unique final, you need the practice to understand the tongue position of the final “ê” (the international phonetic alphabet is [ɛ]) .

4. yi, yin, ying, wu: These four syllables are composed of the finals i, in, ing, and u. Using y or w as initial is to make the spelling unique, that is not to confuse liwu with liu.

5. yu, yue, yun, yuan: These four syllables are composed of the finals ü, üe, ün, and üan, without other initials, y is used and ü is spelled as u. yu(与), yue(月), yun(云), yuan(原)

PS: The unique final do not include yan but it is quite unique. The a in yan is neither equivalent to a nor ê, but the international phonetic symbol [æ]. The international phonetic symbol of an in yan is [æn], it is not (安) but (恩), and y here is i,  so “y(衣)+ an(æn)(恩)->yan(烟)” , more practice on homophonic characters such as 眼、烟、沿、盐、言、演、严、咽、淹、炎.