Zelenskyy talked about a law respecting minority languages in Ukraine, to help the negotiations. So according to the current language policy, introduced by Poroshenko:

Media: either exclusively in Ukrainian or have a Ukrainian language version. Quota for Ukrainian language content for national tv from 75% to 90%.

Movies and theater: Movies must be in Ukrainian or dubbed in Ukrainian. Performances and events must be in Ukrainian, songs in other languages as well.

Education: Schools, universities must teach in Ukrainian.Classes in ethnic minority languages allowed.

Contrary to the minority languages which are EU official languages, Russian, Byelorussian and Yiddish are granted no exemption for the purposes of the law.

More details: https://www.kyivpost.com/ukraine-politics/parliament-passes-ukrainian-language-bill.html and https://en.m.wikipedia.org/wiki/Language_policy_in_Ukraine