Writing Pinyin: Tone Marks, ü, and the Apostrophe | Chinese (Mandarin) Grammar

Once you understand that a pinyin syllable is an initial + a final + a tone, the next step is learning to write it correctly. Pinyin has firm, unglamorous spelling conventions — where the tone mark sits, when the letter ü loses its dots, and when an apostrophe is required — and these are not optional flourishes. They are the rules of the romanization, and two of them (the umlaut and the apostrophe) carry genuine, meaning-bearing information. Getting them right marks the difference between pinyin that a Chinese teacher nods at and pinyin that looks like a guess.

Where the tone mark goes

Every full syllable's tone mark sits on exactly one vowel — the main vowel of the final. When a final has only one vowel, there is no question (mǐ 米, tù 兔, hé 河). The rule only bites when a final has two or three vowel letters and you must decide which one wears the mark. Use this priority:

a beats everything. If there's no a, o takes it. If there's no a or o, e takes it. Otherwise the mark goes on the last of i / u / ü.

A handy way to remember it: "a, o, e, then i, u, ü" — scan the final left to right in that order of priority and mark the first one you hit.

Final has…	Mark goes on	Example
an a	the a	好 hǎo, 快 kuài, 爱 ài
no a, but an o	the o	狗 gǒu, 都 dōu
no a/o, but an e	the e	学 xué, 谢 xiè, 给 gěi
only i, u, ü	the last one	你 nǐ, 路 lù, 绿 lǜ

好

hǎo

good — the final is 'ao'; a wins, so the mark sits on the a: hǎo.

学

xué

to study — the final is 'üe' (written ue after x); no a or o, so e takes the mark: xué.

The iu / ui tie-break

There is one situation the priority list doesn't settle: the finals iu and ui, which each hold two of the equal-ranked vowels i and u. The rule is simple and worth memorising outright: the mark goes on the second letter. So iu → the u is marked, and ui → the i is marked.

六

liù

six — iu, so the mark goes on the second letter, the u: liù (never líu).

对

duì

correct / right — ui, so the mark goes on the second letter, the i: duì (never dùi).

喝酒

hējiǔ

to drink alcohol — 酒 jiǔ is 'iu', so the mark lands on the u: jiǔ.

💡

One more small thing: when the tone mark lands on i, the little dot disappears — you write nǐ, xǐ, bǐ, not the i with both a dot and a tone mark. The tone mark replaces the dot.

The letter ü: when the dots stay and when they vanish

Pinyin has a sixth vowel letter, ü (an "ee" sound made with rounded lips — the sound of 女 nǚ, 绿 lǜ, 鱼 yú). In writing it behaves in a way that trips up nearly every beginner, because the dots are sometimes written and sometimes dropped, depending purely on which initial precedes them.

The dots disappear after j, q, x, and y. These four initials can only combine with the ü sound — they never take a plain u — so there is no ambiguity, and pinyin drops the umlaut to save ink. The letter is written u, but it is still pronounced ü.

去

qù

to go — pronounced with ü, but after q the umlaut is dropped, so it's written qù.

鱼

yú

fish — the ü sound; after y it's written plain u (yú), no dots.

学习

xuéxí

to study — 学 xué hides a ü: the final is üe, written ue after x.

The dots must stay after n and l. Here the umlaut is doing real, indispensable work, because n and l can take both plain u and ü, and the two are different words. Drop the dots and you have written a different syllable.

Plain u	ü (dots required)
努 nǔ — to exert	女 nǚ — woman
路 lù — road	绿 lǜ — green

我女儿六岁了。

Wǒ nǚ'ér liù suì le.

My daughter is six. (informal) — 女 must keep its umlaut (nǚ), or it becomes 努 nǔ.

你喜欢喝绿茶吗？

Nǐ xǐhuan hē lǜchá ma?

Do you like green tea? (informal) — 绿 is lǜ with the dots; lù would be 'road tea'.

💡

The umlaut on nǚ and lǜ is not decoration — it distinguishes the word from nǔ and lù. Never drop the dots after n or l. After j, q, x, y, though, always drop them: 去 is qù, not qǜ.

Standing alone, the ü sound is written yu (with the y device from the syllable-structure page): 雨 yǔ "rain", 语 yǔ "language". The sound itself, and how to make it, is on the ü final.

The apostrophe: keeping syllable boundaries clear

Because pinyin runs the syllables of a word together, a reader occasionally can't tell where one syllable ends and the next begins. Pinyin solves this with a syllable-dividing apostrophe (隔音符号, géyīn fúhào), inserted before a syllable that begins with a, o, or e when it could otherwise glom onto the previous syllable.

The textbook case is the city 西安:

西安

Xī'ān

Xi'an (the city) — two syllables, xī + ān. The apostrophe stops it being read as the single syllable 'xian'.

Without the apostrophe, "Xian" would read as one syllable, xiān (先 "first", 鲜 "fresh"). The apostrophe forces the two-syllable reading xī-ān. The same logic applies wherever an a/o/e-initial syllable follows a vowel:

我们打算去天安门。

Wǒmen dǎsuàn qù Tiān'ānmén.

We plan to go to Tiananmen. (neutral) — 天安门 is Tiān + ān + mén; the apostrophe marks the ān boundary.

这件皮袄很暖和。

Zhè jiàn pí'ǎo hěn nuǎnhuo.

This leather coat is very warm. (everyday) — pí'ǎo = pí + ǎo, not 'piao'.

The apostrophe is only ever needed before a, o, e — the vowels that can legally start a bare final — so you will never see it before an i-, u-, or consonant-initial syllable. It takes no space and is never a possessive; it is purely a boundary marker.

Putting it together

Watch a single everyday sentence exercise all three rules at once:

我们去西安旅游，想喝绿茶。

Wǒmen qù Xī'ān lǚyóu, xiǎng hē lǜchá.

We're travelling to Xi'an and want to drink green tea. (informal)

去 qù — ü written plain u after q.
西安 Xī'ān — apostrophe splits the two syllables.
旅游 lǚyóu — 旅 keeps its umlaut after l; 游 is yóu (ou → o takes the mark).
绿茶 lǜchá — 绿 keeps its umlaut after l; the mark on chá sits on the a.

Common Mistakes

1. Dropping the umlaut after n or l. This writes a different word. 女 is nǚ; drop the dots and you have written 努 nǔ. 绿 is lǜ; without dots it is 路 lù.

❌ 女 → nu

Incorrect — 女 must be written nǚ; 'nu' spells 努 (nǔ), a different word.

✅ 女

nǚ

woman — the umlaut is required after n.

2. Adding an umlaut after j, q, x, y. These initials only take the ü sound, so the dots are always dropped. Writing qǜ or jǜ is over-correct — it should be qù, jù.

❌ 去 → qǜ

Incorrect — after q the umlaut is never written; it's qù.

✅ 去

qù

to go — plain u after q, still pronounced ü.

3. Misplacing the tone mark on iu / ui. The mark goes on the second vowel. It's liù and duì, never líu or dùi.

❌ 对 → dùi

Incorrect — for ui the mark goes on the second letter: duì.

✅ 对

duì

correct — the mark sits on the i of ui.

4. Reading Xi'an (西安) as one syllable. The apostrophe is telling you it is two syllables, xī-ān, not the single syllable xiān. Ignoring the apostrophe collapses a two-character word into one.

5. Marking the wrong vowel in a compound final. In hǎo, gǒu, xué, the mark is decided by the priority a > o > e > i/u/ü, not by which vowel comes first or last. Writing haǒ or guǒ... for 狗 (which is gǒu) puts the accent on the wrong letter.

❌ 狗 → góu (mark drifting off the o)

Incorrect placement — in 'ou' the o outranks the u, so it's gǒu.

✅ 狗

gǒu

dog — o takes the tone mark in the final 'ou'.

Key Takeaways

The tone mark goes on the main vowel by priority a > o > e > i/u/ü; for iu and ui, it lands on the second letter (liù, duì). The dot on i vanishes under a tone mark.
ü loses its dots after j, q, x, y (qù, xǔ, yú) — always still pronounced ü — but keeps them after n and l (nǚ, lǜ), where they distinguish the word from nǔ, lù.
An apostrophe separates syllables before an a/o/e-initial syllable when the boundary is unclear: Xī'ān, Tiān'ānmén, pí'ǎo.
These are spelling rules of the romanization, but the umlaut and the apostrophe carry real meaning — never treat them as optional.

Now practice Chinese

Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.

Start learning Chinese→