Tone sandhi: when written tones change in speech

By the HanTrace team · Updated October 25, 2026

Pinyin is a map, not a recording. Dictionaries and textbooks almost always print the original tone of every syllable — but in real speech, some tones automatically change depending on their neighbors. This mismatch is rarely pointed out, and it causes endless confusion: you memorized nǐ hǎo, yet every native speaker around you says something that sounds like ní hǎo.

Three rules cover nearly everything a learner needs: two third tones in a row, the tone change of 一, and the tone change of 不.

1. Two third tones in a row

When two third tones meet, the first one is pronounced as a rising second tone. The pinyin still shows two third tones — you have to apply the rule yourself:

• nǐ hǎo (“hello”) — pronounced ní hǎo
• wǒ hěn hǎo (“I’m fine”) — the first two syllables group together: pronounced wó hén hǎo

With three or more third tones, how you group the words decides the result. zhǎnlǎnguǎn (“exhibition hall”) is grouped 2+2+3, and wǒ hěn hǎo is 3+2+3. Grouping follows meaning, so listen for word boundaries rather than memorizing formulas.

2. The half-third tone

A third tone only gets its full dipping-then-rising shape when it stands alone or comes at the end of a phrase. Before a first, second, fourth, or neutral tone, it just dips low and stops — the lǎo in lǎoshī (teacher) never rises. This “half third” is by far the most common third tone you will hear, yet beginners keep trying to produce the full rise and end up sounding unnatural.

3. 一 (yī): the moving tone

一 is first tone (yī) when counting or in ordinals like dì-yī (first). In front of another syllable, it changes:

• yí before a fourth tone: yí ge (一个, one [piece])
• yì before first, second, or third tones: yìtiān (一天, one day), yìnián (一年, one year), yìqǐ (一起, together)

4. 不 (bù): one simple rule

不 stays fourth tone (bù) everywhere except before another fourth tone, where it becomes second tone (bú):

• bù chī (不吃, not eat) — stays bù
• bú shì (不是, not be) — becomes bú
• bú huì (不会, not able) — becomes bú

How to train your ear for it

Sandhi is invisible in pinyin but obvious in audio — which is why listening beats staring at tone charts. Two things on this site can help:

• On every character and word page, the audio plays the natural spoken form — for multi-syllable words the recording follows real sandhi, so yìqǐ sounds like speech, not like two dictionary tones glued together.
• Tone Practice drills minimal pairs — syllables that differ only by tone — which is the fastest way to hear tone contrasts before sandhi shifts them.

Once you can hear the four tones reliably, sandhi stops feeling like extra rules and starts feeling like what it actually is: the language smoothing itself out so it is easier to say.