Rockstar has not confirmed whether GTA 6 will include Russian as a supported language. The official list of languages for the game has not been published, so any claim about Russian subtitles or a Russian interface is speculation at this point. What is known is that earlier Rockstar titles, such as GTA 5 and Red Dead Redemption 2, shipped with Russian subtitles, which sets a precedent but does not guarantee the same for GTA 6.
The absence of a confirmed language list means players should treat any reports of Russian support as unverified. The game’s engine, often reported as RAGE, is not officially named by Rockstar, and language support is a separate matter from technical details. Until Rockstar makes an official announcement, the safest assumption is that the game will launch with English at minimum, but other languages may or may not be included.
In practice, players who need Russian will have to wait for Rockstar to release the full language details closer to the launch date. If Russian is not included, community translations or mods may appear after release, but those are not official and carry risks. For now, the only confirmed facts are the release date, platforms, and pricing, all of which are detailed on the release date and price pages. No language list has been announced, so plan accordingly.