Main Vowels & Diphthongs | Chinese (Mandarin) Grammar

Mandarin builds its whole inventory of finals out of just six vowel letters — a, o, e, i, u, ü — plus a handful of glides and endings. That is very good news: six vowels is fewer than English has. But there are two catches, and this page is about both. First, when two vowels sit together they form a diphthong — a single gliding sound, not two separate vowels. Second, one letter does not always spell one sound: the letter e in particular is a shape-shifter, and giving it a single English value everywhere is the fastest way to sound foreign. Learn the vowels as they behave inside finals, and the system becomes reliable.

The six vowel letters

Letter	Core value	Rough English hook	Example
a	open "ah"	the a in father	他 tā "he"
o	rounded "aw / waw"	the aw in law, lips rounded	波 bō "wave"
e (alone)	back unrounded "uh"	the uh in duh / British er	河 hé "river"
i	clear "ee"	the ee in see	你 nǐ "you"
u	rounded "oo"	the oo in too	五 wǔ "five"
ü	"ee" with rounded lips	German über, French lune	女 nǚ "woman"

Two of these get their own pages because English speakers systematically mishear them: the letter i is not always "ee" (after z/c/s and zh/ch/sh/r it is a buzz — see The Three Sounds of Final -i), and ü is a sound English lacks entirely (see the ü final). This page focuses on a, o, e and the diphthongs they build.

他有五个孩子。

Tā yǒu wǔ gè háizi.

He has five children. — 他 tā (open 'ah'), 五 wǔ (rounded 'oo'). (informal)

The four main diphthongs: glide, don't chop

A diphthong is one vowel that moves — your mouth starts in one position and slides to another without a break. English has these too (the vowel in "eye" or "cow"), but English learners tend to over-articulate the second half of a Mandarin diphthong, turning one sound into two. Keep them smooth.

Final	Glides from → to	Sounds like	Example
ai	a → i	"eye"	爱 ài "love"
ei	e → i	"hey"	给 gěi "give"
ao	a → o	"cow / ow"	好 hǎo "good"
ou	o → u	"go / low"	走 zǒu "walk"

我买了两个苹果。

Wǒ mǎi le liǎng gè píngguǒ.

I bought two apples. — 买 (mǎi): the 'ai' diphthong, one smooth 'eye', not 'ma-ee'. (informal)

请给我一杯水。

Qǐng gěi wǒ yì bēi shuǐ.

Please give me a glass of water. — 给 gěi and 杯 bēi: the 'ei' glide, like English 'hey'. (informal)

今天天气真好。

Jīntiān tiānqì zhēn hǎo.

The weather's really nice today. — 好 (hǎo): 'ao' glides a→o as one sound, 'how'. (informal)

我们一起走吧。

Wǒmen yìqǐ zǒu ba.

Let's go together. — 走 (zǒu): 'ou' glides o→u, like the vowel in 'go'. (informal)

那只猫很可爱。

Nà zhī māo hěn kě'ài.

That cat is so cute. — 猫 māo ('ao') and 爱 ài ('ai'): two clean glides in one sentence. (informal)

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Test yourself with a mirror: for a diphthong your lips should be moving throughout the vowel. If they snap to a fixed position and stop, you've frozen the glide into a single vowel — say 好 (hǎo) and watch your jaw open then close a touch. That movement is the sound.

The chameleon letter e

This is the vowel that catches nearly every learner, because pinyin uses the single letter e for two clearly different sounds, decided by the final it sits in.

Alone (and in -en, -eng), e is a back, unrounded "uh" — the sound written in IPA as [ɤ], close to the vowel English speakers make in "duh," "uh," or a British "er." It is made toward the back of the mouth with the lips relaxed and unrounded. This is the default e: 河 (hé) "river," 饿 (è) "hungry," 喝 (hē) "drink," 了 (le, the particle).

这条河很长。

Zhè tiáo hé hěn cháng.

This river is very long. — 河 (hé): the back 'uh' e, not 'ay' and not 'eh'. (informal)

我饿了，想吃饭。

Wǒ è le, xiǎng chīfàn.

I'm hungry, I want to eat. — 饿 (è) and 了 (le): both the relaxed back 'uh'. (informal)

But inside ie and üe, e becomes a front "eh" — the vowel of English "bed" or "yes" [ɛ]. Here the preceding glide pulls the vowel forward. So 谢 (xiè) "thanks" is "shyeh," 月 (yuè) "moon" is "yweh," 也 (yě) "also" is "yeh," 学 (xué) "study" is "shweh." Give these an "uh" and they sound wrong instantly.

谢谢你！

Xièxie nǐ!

Thank you! — 谢 (xiè): the 'ie' e is a front 'eh' ('shyeh'), never 'shyuh'. (informal)

十五的月亮很圆。

Shíwǔ de yuèliang hěn yuán.

The moon on the 15th is beautifully round. — 月 (yuè): the 'üe' e is 'eh' ('yweh'). (informal)

我也想去。

Wǒ yě xiǎng qù.

I want to go too. — 也 (yě): 'ie' → front 'eh' ('yeh'). (informal)

There is one more member of the e family worth naming: the e in ei is also a front vowel ("hey," as we saw above). So the honest summary is: e is a back "uh" on its own and in the nasals -en/-eng, but a front "eh" whenever a glide precedes it (ie, üe, ei). Do not look for a single English value — look at the final.

A quick word on o

The letter o is rounder than English speakers expect. On its own and after b/p/m/f it carries a slight w-onset: 波 (bō) is closer to "bwaw" than a flat "boh," and the interjection 哦 (ó) is "aw" with rounded lips. Meanwhile the uo final (说 shuō, 我 wǒ) is a full glide from u to o — "shwaw," "waw." Keep the lips rounded and you will be right.

你说什么？

Nǐ shuō shénme?

What did you say? — 说 (shuō): the 'uo' final, a rounded 'shwaw'. (informal)

Common Mistakes

1. Giving e one fixed value everywhere. The biggest e-error: saying 谢 (xiè) with a back "uh" ("shyuh"), or 河 (hé) with a front "eh" ("hay/heh"). Let the final decide — "uh" alone, "eh" after a glide.

谢

xiè

thanks. ❌ 'shyuh' (back e) → ✅ 'shyeh' (front 'eh' in ie).

2. Chopping ao into "ah-oh." 好 (hǎo) is one gliding "how." Two separate vowels turn one syllable into two beats.

好

hǎo

good. ❌ 'ha-o' → ✅ 'how' (single glide).

3. Chopping ou into "oh-oo." 走 (zǒu) is "dzoh," a smooth o→u, not "dzo-oo."

走

zǒu

to walk / go. ❌ 'dzo-oo' → ✅ 'dzoh' (one glide, like 'go').

4. Reading ei as "ee." 给 (gěi) is "gay/gey," not "gee." The final is the glide of English "hey," not the pure vowel of "see."

给

gěi

to give. ❌ 'gee' → ✅ 'gay' (the 'ei' glide, as in 'hey').

5. Flattening o into a pure "oh." Mandarin o is rounded and often w-colored: 波 (bō) is "bwaw," 我 (wǒ) is "waw," not a flat "boh / oh."

我

wǒ

I, me. ❌ flat 'oh' → ✅ rounded 'waw' (the uo final).

Key Takeaways

Six vowel letters — a o e i u ü — build every final; learn each as it behaves inside its final.
The four core diphthongs glide as one sound: ai "eye," ei "hey," ao "how," ou "go." Don't chop them.
The letter e is a chameleon: a back "uh" alone and in -en/-eng (河 hé, 饿 è), but a front "eh" after a glide in ie / üe / ei (谢 xiè, 月 yuè, 给 gěi).
o is rounded and often w-colored (波 bō "bwaw," 我 wǒ "waw").
The letter i (a buzz after z/c/s/zh/ch/sh/r) and ü each have their own page — don't assume "ee" and "oo" cover them.

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