Pinyin is a remarkably consistent system, but it has a layer of spelling conventions that confuse learners: why the same vowel is written i, yi or y; why ü sometimes loses its dots; and why the tone mark sits on the second vowel in guì but the first in gǒu. These rules affect reading, typing and looking up words, and once learned they take seconds to apply.
Rule 1: y and w at the start of syllables
When a syllable has no initial consonant and begins with i, u or ü, pinyin changes the spelling so that syllable boundaries are unambiguous:
| Final | Written as | Examples |
|---|---|---|
| i, in, ing | yi, yin, ying (add y) | |
| ia, ie, iao, iou, ian, iang, iong | ya, ye, yao, you, yan, yang, yong (i → y) | |
| u | wu (add w) | |
| ua, uo, uai, uei, uan, uen, uang, ueng | wa, wo, wai, wei, wan, wen, wang, weng (u → w) | |
| ü, üe, üan, ün | yu, yue, yuan, yun (add y, drop dots) |
The key consequence: yu is never "you". It is always ü. And you in pinyin is pronounced [jou], "yo-u", as in .
Rule 2: when ü loses its dots
ü keeps its dots only after n and l, where both nu/nü and lu/lü exist: vs , vs . After j, q, x and y, there is no possible confusion (these initials never take u), so the dots are dropped: ju, qu, xu, yu. On keyboards where ü is hard to type, v is used: lv4 = lǜ. That is the convention used by most Chinese input methods.
Rule 3: iu, ui and un are abbreviations
After a consonant, the finals iou, uei and uen lose their middle vowel in writing: liou → liu, guei → gui, luen → lun. The vowel is still there in speech, particularly in third and fourth tones: sounds like "lyo-u", like "gway". Without a consonant, the full form reappears with y/w: you, wei, wen.
Rule 4: where the tone mark goes
A syllable has one tone mark, placed on its main vowel. The rule can be stated in three steps:
- If there is an a or e, it takes the mark: hǎo, xiè, guān, léi, yuè. (a and e never appear together.)
- If there is ou, the o takes the mark: gǒu, yǒu, zhōu. (Note that liù is spelled iu, not ou, so the next step applies to it.)
- Otherwise, the last vowel takes the mark: liù, guì, duō, huó.
| Syllable | Correct | Why |
|---|---|---|
| hao3 | hǎo | a takes it |
| xie4 | xiè | e takes it |
| gou3 | gǒu | ou: mark the o |
| gui4 | guì | no a, e or ou: last vowel |
| liu4 | liù | no a, e or ou: last vowel |
| lve4 | lüè | e takes it; v is written ü |
| er2 | ér | e takes it |
The neutral tone has no mark: ma, de, le. Some older texts put a dot before the syllable to show it.
Rule 5: the apostrophe
When a syllable beginning with a, o or e follows another syllable in the same word, an apostrophe marks the boundary: (not Xian, which could be 先 xiān), , , . Words are written as units: péngyou, not péng you, according to the national orthography standard GB/T 16159.
Capitals and names
Proper names are capitalised and written as one word: Běijīng, Zhōngguó. Personal names put the surname first and write the given name as one word: Wáng Xiǎomíng. In everyday English contexts, tone marks are usually omitted: Beijing, Xi'an.
Spell it in pinyin
Choose an answer to see the explanation.
1. How is the syllable i + third tone written on its own?
- ǐ
- yǐ
- ǐy
Answer: yǐ. A syllable beginning with i adds y: 以 yǐ.
2. Where does the tone mark go in dui4?
- dùi
- duì
Answer: duì. No a, e or ou, so the last vowel takes the mark.
3. How do you write "ü" + fourth tone after l?
- lù
- lǜ
- lüè
Answer: lǜ. After n and l, the dots stay: 绿 lǜ.
4. How is 去 written?
- qǜ
- qù
- chù
Answer: qù. After q, ü is written u without dots.
5. Why does Xī'ān need an apostrophe?
- To show the tone
- To show that ān is a separate syllable
- It is a proper name
Answer: To show that ān is a separate syllable. Without it, xian could be read as one syllable.
Frequently asked questions
Where does the tone mark go in pinyin?
On a if there is one; otherwise on e; in ou, on the o; otherwise on the last vowel. So hǎo, xiè, gǒu, guì, liù.
Is "y" a consonant in pinyin?
Mostly it is a spelling device. Syllables that begin with i, u or ü are written with y or w so that syllable boundaries are clear: yi, ya, ye, you, wu, wa, wo, wei, yu, yue. The y and w represent the glides [j] and [w] at most.
Why is 西安 written Xi'an?
Without the apostrophe, xian would be read as one syllable (like 先 xiān). The apostrophe shows that a new syllable starting with a, o or e begins here: Xī'ān.
Sources and further reading
- State Council of the People's Republic of China (1958). Hanyu Pinyin Fang'an (Scheme for the Chinese Phonetic Alphabet).
- General Administration of Quality Supervision and Standardization Administration of China (2012). GB/T 16159-2012: Basic rules of the Chinese phonetic alphabet orthography.
- DeFrancis, J. (ed.) (2003). ABC Chinese-English Comprehensive Dictionary, introduction on pinyin. University of Hawai'i Press.
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