The Question Particle Ли

ли is the particle that turns a statement into a yes-no question and, just as importantly, the word Russian uses for the English "whether / if" inside an indirect question. It is enclitic — unstressed, leaning on the word in front of it — and its placement is rigid: the word being questioned moves to the front of the clause and ли latches on right behind it. Two facts trip up almost every English speaker: first, in ordinary spoken yes-no questions Russian usually drops ли and relies on rising intonation; second, the "if" of "I don't know if he'll come" is never е́сли in Russian — it is ли. Get those two reflexes right and ли becomes one of the most useful words you own.

Direct yes-no questions: formal or emphatic

You can form a yes-no question with ли, and when you do it sounds bookish, formal, or emphatic. The pattern is: take the word you're actually asking about, front it, attach ли, then the rest.

Compare the everyday spoken version, which drops ли and just rises in pitch:

A very common polite use is the negated offer, where Не … ли softens an invitation into "wouldn't you perhaps...":

Indirect questions: ли = "whether / if"

This is where ли is not optional — it is the only correct word. When you report or embed a yes-no question ("I don't know whether he'll come," "Ask if they have time"), Russian fronts the verb (or the focus word) in the embedded clause and attaches ли. There is no separate conjunction; ли is the link.

If the focus of the embedded question is not the verb but some other element, that element fronts instead — exactly as in direct questions:

The trap: "if" ≠ е́сли here

English uses one word, if, for two different jobs: the conditional ("if it rains, we'll stay") and the indirect question ("I don't know if it'll rain"). Russian splits these. е́сли is only the conditional "if." For the indirect-question "if" — the one you could swap for "whether" — you must use ли. Swapping in е́сли here is one of the most common and most audible English-speaker errors.

Test yourself with the English: if you can replace "if" with "whether" and the sentence still works, Russian needs ли; if you can't, it's a condition and needs е́сли.

то ли … то ли and вряд ли

ли also lives inside two fixed expressions worth knowing early. то ли … то ли marks an uncertain "either … or" — the speaker can't decide which is true:

And вряд ли is a frozen phrase meaning "hardly / unlikely / I doubt it":

The distinguishing insight: ли writes the question-mark inside the clause

English signals an embedded question with the word order alone — "I wonder whether he is at home" keeps statement order and just adds whether. Russian instead inverts the embedded clause to question order (verb first) and stamps ли on it, so the embedded clause physically looks like a question turned inward: придёт ли он is literally "will-come ли he." Think of ли as a portable question particle: in a direct formal question it makes the main clause interrogative; embedded, it makes the subclause interrogative. Once you see that ли and the fronting always travel together, both uses become one rule — **front the questioned word, attach ли — and the е́сли trap dissolves, because conditionals are never questions and so never take ли.

Common Mistakes

Key Takeaways

• ли is the yes-no question particle and the indirect-question "whether/if" marker; it is enclitic and never starts a clause.
• It follows the fronted questioned word — usually the verb: Зна́ете ли вы…, придёт ли он.
• Direct ли-questions sound formal/emphatic; everyday spoken yes-no questions drop ли and use rising intonation.
• For indirect questions ли is mandatory — and the "if" there is never е́сли. Swap-test: if English "if" = "whether," use ли; if it's a condition, use е́сли.
• Fixed phrases: то ли … то ли (uncertain either/or), вряд ли (hardly, unlikely).
• The polite negated offer Не … ли (Не хоти́те ли…?) is a gracious way to invite.