Third Tone Sandhi: When 3rd Tone Changes
The most important tone change rule in Mandarin
Category: Tones & Pronunciation
The Rule
When two 3rd tones appear in sequence, the first 3rd tone changes to a 2nd tone. The pinyin spelling does NOT change — only the pronunciation does.
Why This Matters
This is a mandatory rule, not optional. Native speakers do this automatically and will find it jarring if you don't. English has similar phenomena (like how 'input' stress shifts), but Chinese tone sandhi is much more systematic and must be learned explicitly.
Examples
• 你好 (nǐ hǎo → ní hǎo) — "hello" [Written as 3rd+3rd, spoken as 2nd+3rd] • 可以 (kě yǐ → ké yǐ) — "can / may" [The 可 changes from 3rd to 2nd tone in speech] • 很好 (hěn hǎo → hén hǎo) — "very good" [很 shifts to 2nd tone before 好] • 洗手 (xǐ shǒu → xí shǒu) — "wash hands" [洗 becomes 2nd tone before 手]
Common Mistakes
❌ Pronouncing both syllables with full 3rd tone dip: nǐ hǎo ✅ Change the first to rising: ní hǎo → Two consecutive dipping tones are physically difficult and unnatural. Native speakers never do this — it immediately marks you as a beginner. ❌ Writing the changed tone in pinyin: ní hǎo ✅ Write the original tone: nǐ hǎo, but pronounce it as ní hǎo → Pinyin always shows the underlying (dictionary) tone. Sandhi is a pronunciation rule, not a spelling rule.
Quick Tip
When you see two 3rd-tone syllables in a row, immediately think: first one becomes 2nd tone. No exceptions.
When you see two 3rd-tone syllables in a row, immediately think: first one becomes 2nd tone. No exceptions.
Examples
Common Mistakes
Incorrect: Pronouncing both syllables with full 3rd tone dip: nǐ hǎo → Correct: Change the first to rising: ní hǎo. Two consecutive dipping tones are physically difficult and unnatural. Native speakers never do this — it immediately marks you as a beginner.
Incorrect: Writing the changed tone in pinyin: ní hǎo → Correct: Write the original tone: nǐ hǎo, but pronounce it as ní hǎo. Pinyin always shows the underlying (dictionary) tone. Sandhi is a pronunciation rule, not a spelling rule.
Quiz
How is 可以 (kě yǐ) actually pronounced?