Je suis si fatigué ce soir.

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Breakdown of Je suis si fatigué ce soir.

• être: to be
• fatigué: tired
• ce soir: tonight

Questions & Answers about Je suis si fatigué ce soir.

Why is si used here, and how is it different from très or tellement?

In this sentence, si means so, as in so tired.

• Je suis si fatigué ce soir. → I am so tired tonight.
• Je suis très fatigué ce soir. → I am very tired tonight.

Très is more neutral and common, like very.
Si is often a bit more emotional or expressive, like stressing the intensity.
You can also say tellement (also so / so much), which feels quite strong:

• Je suis tellement fatigué ce soir. → I’m so / really tired tonight.

All three are grammatically correct; the difference is nuance and emphasis, not grammar.

If a woman is speaking, does the sentence change?

Yes, the adjective must agree with the gender of the speaker.

• Man: Je suis si fatigué ce soir.
• Woman: Je suis si fatiguée ce soir.

The feminine form fatiguée has an extra e at the end.
In normal speech, fatigué and fatiguée are pronounced the same; the extra e is only visible in writing.

Why does fatigué have an accent, and how do you pronounce it?