Mandarin Tone Sandhi: The Tone Change Rules
In real Mandarin, tones don’t always stay put — they shift depending on the tone that follows. Here are the three tone-change rules that make you sound natural, with audio for every example.
In short
Tone sandhi (变调 biàndiào) is when a syllable’s tone changes because of the tone next to it. Three rules cover almost everything: third-tone sandhi (你好 nǐ hǎo → ní hǎo), 不 (bù → bú before a 4th tone), and 一 (yī → yì or yí depending on what follows).
The big idea: underlying vs surface tone
Every syllable has an underlying tone — the one in the dictionary. But in connected speech, some tones change to a surface tone that’s easier to say. The meaning never changes; only the sound does. Master the three rules below and your Mandarin will instantly sound smoother.
1. Third-tone sandhi
This is the big one. When two third tones sit side by side, the first one becomes a second (rising) tone. The second keeps its third tone.
The “half-third” tone — the one nobody teaches you
Here’s the secret behind why your third tones sound off: a third tone before a 1st, 2nd, 4th or neutral tone isn’t the big “dip”. You only say the first half — it drops low and stops, with no rise. The full dipping third tone really only appears on its own or at the end of a phrase. In running speech, most third tones are this low “half-third”.
Three third tones in a row
With three third tones, group by meaning, then apply the rule inside each group. If the first two form a word, it’s 2-2-3; if the last two form a word, it’s 3-2-3.
2. The 不 (bù) rule
不 is normally a 4th tone (bù). It flips to a 2nd tone (bú) when the next syllable is also a 4th tone. Before everything else, it stays bù.
3. The 一 (yī) rule
一 has three jobs. On its own — counting, dates, ordinals — it stays yī. In front of another syllable it shifts.
Stays 1st tone (yī)
Counting, digits, ordinals and dates: 第一 dì yī (first), 一月 yī yuè (January), 星期一 xīngqī yī (Monday), 一二三 yī èr sān.
Becomes 4th tone (yì) — before 1st, 2nd or 3rd
Becomes 2nd tone (yí) — before a 4th tone
A quick word on the neutral tone
The neutral tone (轻声 qīngshēng) is short, light and has no fixed pitch of its own — its height depends on the tone before it. You’ll meet it most in particles (吗, 了, 的, 吧), reduplicated family words (妈妈, 哥哥) and some suffixes (桌子 zhuōzi, 我们 wǒmen).
Does tone sandhi show in pinyin?
Third-tone sandhi: no. Tone marks stay as the underlying tone — you write 你好 as nǐ hǎo and apply the change yourself. 不 and 一: it varies. Some materials keep the base tones (bù, yī); many learner textbooks write them as pronounced (bú shì, yí dìng, yì tiān). On this site we write 不 and 一 as pronounced to help you hear the change — but never re-mark third-tone sandhi.
Five common mistakes, fixed
✕Saying the full “dip” on every 3rd tone
In speech, most third tones are the low half-third. Save the full dip for syllables on their own or at the end.
✕Forgetting to raise the first 3rd tone
你好 is ní hǎo, not nǐ hǎo. Two thirds in a row → the first rises.
✕Keeping 不 as bù before 4th tones
不是 is bú shì. Only flips before a 4th tone — nowhere else.
✕Treating 一 as one fixed tone
It’s yī / yì / yí depending on the next syllable. Look right, then decide.
✕Toning 一个 as yì ge
It’s yí ge — 个’s hidden 4th tone triggers the 2nd-tone change.
✕Re-writing third-tone marks
Never change the written tone for third-tone sandhi — only your pronunciation shifts.
Quick quiz
Test your tone sandhi
1. How is 你好 actually pronounced?
2. What tone is 不 in 不是?
3. How is 一 pronounced in 一定?
FAQs
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