Chinese Sentence Lab

You wrote a Mandarin sentence and want a straight answer: is it correct, is it natural, and what is the smallest change that fixes it? The Sentence Lab is SayMei's free Chinese grammar checker (中文语法检查) built around that one question. Paste up to 300 characters of hanzi, simplified or traditional, pinyin with or without tone marks, or a short English idea. Back comes a verdict — natural, unnatural, needs correction, or meaning unclear — with the exact change marked. No account needed.

Six mistakes English speakers make in Mandarin

These are the errors it flags most often.

• Time goes before the verb. 我去北京昨天 → 我昨天去北京 (Wǒ zuótiān qù Běijīng). Time and place are stated ahead of the action, never tacked on the end.
• No 是 in front of an adjective. 我是忙 → 我很忙 (Wǒ hěn máng). 是 joins two nouns. An adjective is its own predicate, and 很 is the neutral link, not "very".
• Nouns take their own measure word. 三个书 → 三本书 (sān běn shū). 个 is the fallback classifier, but books take 本, flat things take 张, long things take 条.
• 了 marks aspect, not past tense. 我每天喝了咖啡 → 我每天都喝咖啡 (Wǒ měitiān dōu hē kāfēi). 了 signals one completed event, so it cannot sit inside a habit.
• 得 must follow its verb directly. 我说中文得很好 → 我中文说得很好 (Wǒ Zhōngwén shuō de hěn hǎo). Move the object in front, or repeat the verb: 我说中文说得很好.
• 比 comparisons take a bare adjective. 他比我很高 → 他比我高 (Tā bǐ wǒ gāo). Degree goes after it — 高一点儿, 高得多 — and never 很 in front.

Why the verdict is trustworthy

The facts come from data, not a model's guess. SayMei's dictionary segments your input word by word with meanings and HSK levels; a converter writes the pinyin. The model judges only naturalness and the minimal edit, and must pass trust rules: anything marked correct comes back character for character, and a "smallest fix" that rewrites most of the sentence is rejected. Grammar problems stay separate from style preferences.

Limits, and what to do with the result

Toneless pinyin is labelled a best guess, an ambiguous sentence gets one clarifying question instead of an invented reading, and if AI review fails you still get the dictionary breakdown, not a fake verdict. A full result ends with two contrastive examples and two drills; say them aloud in live Chinese speaking practice. For a whole paragraph use the Text Analyzer, for classifiers the Measure Word Finder, for tone changes the Tone Sandhi Checker, or browse every free Chinese learning tool.

Frequently asked questions

What does the Chinese Sentence Lab check?

It checks one sentence at a time for grammar and naturalness, keeping the two separate. You get a verdict, the smallest correction, a natural spoken alternative, tone-marked pinyin, an explanation, contrastive examples, and speaking drills.

What happens if my sentence is already correct?

The Sentence Lab tells you it is natural and leaves it unchanged. That lets you distinguish a real grammar error from an optional style choice.

Can I type pinyin instead of Chinese characters?

Yes. You can enter pinyin with tone marks, tone numbers, or no tones. Toneless pinyin can match more than one sentence, so add a short English note when you need to clarify what you mean.

How is the smallest fix different from the natural version?

The smallest fix repairs the actual error while preserving your words. The natural version shows how a native speaker might casually express the same idea. Study both so you learn the rule without losing your own voice.

What is the best way to practice a correction?

Say the original and corrected sentences as a contrast, explain the change in your own words, then use the corrected pattern in a new sentence. Finish by trying that new sentence live with Mei Lin.