Write in your own language.

Write in your language, with everything that carries: your mother tongue, your own way of speaking and writing, whatever you find beautiful, fitting, and expressive. That is, write in your mother tongue and in your own style.

But language in our brains is not sharply defined, so you may have terms and sentences from other languages, such as English, that you find more expressive — there is no harm in writing with them. You can also write with a mix of vocabularies.

And write in the language closest to your mouth, not the most impressive one. If your everyday speech is a dialect, Egyptian or Iraqi or Moroccan or whatever your own town speaks, write in that. A page written in the language you actually think in gets closer to what happened than a page written in a grander one you are still reaching for, and that reaching is exactly the effort that pulls you out of the moment you were trying to record. The exception is real: if a second language genuinely feels better to write in, and you are fluent enough that it costs you nothing, use it. Some people can only say certain things in their second language. What matters is that the language carries you, not that you carry it.