How to use the French word SI

The word si is used all the time in French! However, you may have noticed that it’s not always used the same way. That’s because si has several meanings, and it’s all about context.

Sometimes, SI means YES

Si means yes after negative questions. Once you get the hang of it, you’ll see that using si offers a much clearer response than the way we do it in English.

Imagine that someone asks you, “You’re not too cold?” You may reply by saying yes. If you do that, we’re not quite sure if you’re answering affirmatively or negatively. If you reply by saying no, we still aren’t sure.

Si is also used to deny a negative statement. For example, “Tu n’as pas vidé le lave-vaisselle?” If you have indeed unloaded the dishwasher, you would answer Si! Yes, I did!

Sometimes, SI means SO

Very often, si means so when you want to add intensity to what you’re saying. In this case, it’s also very common to use the word tellement.

J’ai si soif.	I’m so thirsty.
J’ai tellement soif.	I’m so thirsty.

Je n’en peux plus. Je suis si fatigué(e).	I can’t take it anymore. I’m so tired.
Je n’en peux plus. Je suis tellement fatigué(e).	I can’t take it anymore. I’m so tired.

Ton frère est si beau!	Your brother is so good looking!
Ton frère est tellement beau!	Your brother is so good looking!

Sometimes, SI means WHAT IF

Use si when you want to make a suggestion to do something. This is very common, and quite informal. The verb needs to be in the imperfect tense.

Et si on allait au théâtre?	What if we went to the theater?
Et si on partait en week-end?	What if we went away for the weekend?

Most of the time, SI means IF

Si is most commonly used to mean if in si clauses. There are three types of si clauses in French, and they require the use of different tenses.

1st conditionalsi clauses	SI + PRESENT	FUTURE
en français	Si tu viens →	on ira prendre un café.
en anglais	If you come →	we will go for a coffee.

2nd conditionalsi clauses	SI + IMPERFECT	PRESENT CONDITIONAL
en français	Si tu venais →	on irait prendre un café.
en anglais	If you came →	we would go for a coffee.

3rd conditionalsi clauses	SI + PLUS-QUE-PARFAIT	PAST CONDITIONAL
en français	Si tu étais venu(e) →	on serait allé(e)s prendre un café.
en anglais	If you had came →	we would have gone for a coffee.