What Are the Chinese Tone Rules and Tone Sandhi?

You might think that you finally memorized and mastered the Chinese tones. You practiced them over and over again until friends, family and neighbors have started to wonder what's going on, and you now finally feel confident. Then Chinese has a way of throwing a surprise at you. It's that the tones you learned aren't always the tones you actually say. Chinese tones can feel like a musical obstacle course at times. Just when you think you've got the tones and notes and sounds right, the language changes them on you. Learning the four Mandarin tones is only half the battle. Chinese decided that sometimes the tones should change, just to keep things interesting. That's where tone sandhi comes in to help.

One of the trickiest aspects of Mandarin pronunciation is tone sandhi (变调 biàndiào) — the rules that govern when tones change based on the tones around them. Even if you've memorized the dictionary tone for every word, you'll sound unnatural if you don't apply these rules!

Third Tone Sandhi (The Most Important Rule)

When two 3rd tones appear in a row, the first one changes to a 2nd tone:

• 你好 nǐ + hǎo → ní hǎo (hello) — The first 3rd tone becomes 2nd
• 很好 hěn + hǎo → hén hǎo (very good)
• 可以 kě + yǐ → ké yǐ (can/may)
• 所以 suǒ + yǐ → suó yǐ (therefore)

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Transcript

1. What happens when two third tones meet?
2. Hello is written with two third tones.
3. Said together, the first one rises, like a second tone.
4. 你好 (ní hǎo)
5. Very good works the same way.
6. 很好 (hén hǎo)
7. The spelling stays the same, only the sound changes.
8. Two third tones in a row, the first becomes a second.

一 (yī) Tone Changes

The word "one" (一) has three different pronunciations depending on context:

• yī (1st tone) — When counting, at the end of a word, or alone: 一二三 (yī èr sān)
• yí (2nd tone) — Before a 4th tone: 一个 yí gè (one [measure word])
• yì (4th tone) — Before 1st, 2nd, or 3rd tones: 一天 yì tiān (one day), 一年 yì nián (one year)

不 (bù) Tone Changes

The negative word 不 also changes tone:

• bù (4th tone) — Before 1st, 2nd, or 3rd tones: 不吃 bù chī (not eat), 不来 bù lái (not come)
• bú (2nd tone) — Before another 4th tone: 不是 bú shì (is not), 不要 bú yào (don't want)

Half Third Tone

In natural speech, the 3rd tone is rarely pronounced with the full dip-and-rise pattern. Before 1st, 2nd, or 4th tones, it becomes a "half third" — just the low dipping part without rising:

• 老师 lǎo shī — The lǎo is pronounced low without the rise
• 你们 nǐ men — The nǐ dips but doesn't rise

Where to drill the tone changes

Sandhi is a rule about tones next to each other, so the useful practice is on pairs rather than single syllables:

• Sandhi Sprint — hear a real two-syllable word and choose the tone pair people actually say, with the printed pair left among the options.
• The tone sandhi checker — paste your own Chinese or pinyin and see the citation reading aligned with every possible connected reading, with each change explained.
• The tone pairs quiz — hear two tones together and name the pair, which is the unit every rule above operates on.
• Tone pair arcade — the same thing under a clock, with the difficulty climbing as you keep up.
• The tone mirror — say a syllable and see your own pitch drawn against the tone you were aiming for. It is the only one of these that tells you what you did.
• The tone trainer — single-tone recognition, if the four tones are not yet automatic on their own.