In short

Both 也 (yě, also/too) and 都 (dōu, all/both) are adverbs, so they live in the same fixed spot: after the subject and right before the verb - never at the end like English “too,” and never in front of the subject. So “I’m going too” is 我也去 (wǒ yě qù) and “we all go” is 我们都去 (wǒmen dōu qù). Remember one thing about 都: it sums up whatever comes to its left.

The rule

Step 1 - They are adverbs, so they go before the verb. Mandarin puts scope adverbs inside the clause, between the subject and the predicate:

Subject + 也 / 都 + Verb (or 很 + Adj, or 是 + Noun)

You can never park 也 or 都 at the end of the sentence the way English drops “too” or “all” there, and you can never put them ahead of the subject.

Step 2 - 也 (yě) = “also / too,” and it needs a predicate. 也 links a second situation to a first one: 我也去 (wǒ yě qù, I’ll go too). Because it is an adverb, it must have a verb or adjective after it - you cannot answer “me too” with a bare 也. The fix is to supply a predicate, usually 是: 我也是 (wǒ yě shì, me too). It sits before 不 / 没, before 很, and before 是: 我也不去 (wǒ yě bù qù, I’m not going either), 她也很高 (tā yě hěn gāo, she’s tall too).

Step 3 - 都 (dōu) = “all / both,” and it looks LEFT. 都 totalizes a plural word that has already appeared - the subject or a fronted topic. So the plural noun comes first and 都 follows it: 我们都是学生 (wǒmen dōu shì xuéshēng, we’re all students), 他们都来了 (tāmen dōu lái le, they’ve all come). This is why 都我们去 is impossible: there is nothing to its left to sum up. English lets “all” float (“all of us go”); Chinese anchors it after the noun.

Step 4 - Negation scope: where 不 sits changes the meaning. With 都, the order of 都 and 不 decides total vs partial negation:

• 都不 / 都没 = total negation, “none / not any”: 他们都不去 (tāmen dōu bù qù, none of them are going).
• 不都 = partial negation, “not all”: 他们不都去 (tāmen bù dōu qù, not all of them go - some do).

With 也, negation gives English “either / neither”: 我也不去 (wǒ yě bù qù, I’m not going either). Note that 不 is written bù but is pronounced bú before a 4th-tone verb, so 不去 is said bú qù.

Step 5 - Combining them, and the 都…了 pattern. When both appear, the order is fixed as 也都: 他们也都很忙 (tāmen yě dōu hěn máng, they’re all busy too). Separately, 都…了 is an emphatic frame that means “already,” often with a hint of surprise or impatience - here 都 does not mean “all”: 都十点了 (dōu shí diǎn le, it’s already ten o’clock!), 他都走了 (tā dōu zǒu le, he’s already left).

Forms & patterns

Where 也 and 都 sit in the clause:

Negation scope with 都 - the position of 不 flips the meaning:

Examples

Common mistakes

• 我去也。 -> 我也去。 (Wǒ yě qù.) - 也 is an adverb; it goes before the verb, never at the end like English “too.”
• 也我去。 -> 我也去。 - 也 follows the subject, it does not stand in front of it.
• 都我们是学生。 -> 我们都是学生。 - 都 sums up the noun to its left, so the plural subject must come first.
• 我也。 -> 我也是。 - 也 cannot close a clause on its own; “me too” needs a predicate, so add 是.
• 他们不都喜欢咖啡。 (meant as “none of them like it”) -> 他们都不喜欢咖啡。 - 不都 means “not all”; for “none,” negation goes after 都 as 都不.

Tips

• Mnemonic for 都: it looks left. Whatever it totalizes - the whole group - must already be sitting in front of it. If there is no plural word to the left, 都 has nothing to do.
• 也 covers every English polarity word at once: “too,” “also,” “as well,” and in the negative “either / neither.” 我也不知道 (wǒ yě bù zhīdào) = “I don’t know either.”
• The word is dōu (1st tone) for “all.” The same character read dū means “capital city” (as in 首都, shǒudū) - a different word, so keep the tone straight.
• When 也 or 都 lands before a 3rd-tone word, watch the sandhi: 也很好 is written yě hěn hǎo but the stacked 3rd tones shift it to yé hén hǎo in speech.