Tone Sandhi Checker

Pinyin shows every syllable with its dictionary tone, but Mandarin is not spoken that way. A few tone changes — tone sandhi — are automatic for native speakers: 你好 is written nǐ hǎo and said ní hǎo, 不是 is said bú shì, 一个 is said yí gè. Type any Chinese word or sentence above and the checker shows, for every syllable, the dictionary tone and the tone actually spoken, highlights each change and gives the rule behind it in one line.

It applies the three rules every learner meets. Third tone: a 3rd tone before another 3rd tone becomes a rising 2nd tone (3+3 → 2+3). 不 (bù) becomes bú before a 4th tone, and is light in A-not-A questions like 好不好. 一 (yī) becomes yí before a 4th tone and yì before a 1st, 2nd or 3rd, but keeps yī when counting, in ordinals like 第一, in dates and at the end of a phrase.

Long chains of third tones are where textbooks disagree, so here is exactly what the checker does. It splits the chain into words (我也很好 → 我也 | 很好), pairs single-syllable words from the left, says each pair 2+3, and then, right to left, raises any syllable still on a 3rd tone in front of another 3rd tone. That gives wó yě hén hǎo for 我也很好, zhán lán guǎn for 展览馆 and xiǎo láo hǔ for 小老虎. It is one natural reading: in fast speech natives often raise every syllable but the last, and a pause can reset the chain.

Knowing the rule is not the same as saying it. Tap “Say it — get scored” and record the text: each syllable is scored for tone and for its initial and final, against the spoken tones shown above, so you find out whether your 你 really rose. In chains of three or more third tones the score accepts either grouping.

Honest limits. The dictionary tones come from a word-aware pinyin dictionary, so polyphones (characters with more than one reading) are usually but not always right. Syllables that are neutral in everyday speech (东西 as “thing”, the second 谢 of 谢谢, 朋友, 时候) may show their full tone, and the third-tone rule then treats them as full tones (朋友很好 comes out as if 友 were a 3rd tone). 一 and 不 are handled by rule plus a short list of set phrases; other fixed expressions and potential complements (看不见) are not covered. Simplified characters give the most reliable readings.