书面语 vs 口语: written vs spoken register

语体 / register & style

Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral

口语 → 书面语 : 在→于, 这→此, 他的→其, 是→为, 和→与/及, 没有→无/未, 因为→由于/因

Modern Chinese has two sharply different registers. From level 5 you read texts (press, literature, notices) full of monosyllabic words of classical origin:

• 于 = 在/对/比 (位于、高于、有利于)

• 此 = 这 (因此、此时、如此)

• 其 = 他的/它的/其中 (其原因、其他)

• 与 = 和; 及 = 以及; 无 = 没有; 未 = 没/还没; 皆 = 都

• 为 (wéi) = 是/当作

Conversely, speech prefers longer forms and particles (呢、吧、嘛). Switching registers is a key skill at levels 5-6.

Examples

此地位于长江以南，气候温和。
Cǐ dì wèiyú Cháng Jiāng yǐ nán, qìhòu wēnhé.
This place lies south of the Yangtze, with a mild climate.
作者未说明其原因。
Zuòzhě wèi shuōmíng qí yuányīn.
The author didn't explain the reason for it.
口语：这个问题我们还没讨论。→ 书面语：此问题尚未讨论。
Kǒuyǔ: Zhège wèntí wǒmen hái méi tǎolùn. → Shūmiànyǔ: Cǐ wèntí shàng wèi tǎolùn.
Spoken: "We haven't discussed this yet." → Written: "This matter has not yet been discussed."

Common mistakes

✗ Mixing registers: ✗ 此问题我们还没讨论呢 → keep it all spoken or all written.

✗ 其 as a standalone subject: ✗ 其很好 → ✓ 其质量很好 (其 modifies a noun).