The reason this remains a community-driven "exclusive" fix rather than an official patch is largely due to the game's age and its troubled lifecycle. Street Fighter X Tekken suffered from a controversial launch involving on-disc DLC and unbalanced mechanics. Capcom eventually moved on to support Ultra Street Fighter IV and later Street Fighter V , leaving the PC port of SFxT largely abandoned regarding Quality of Life updates like language toggles.
If the method above doesn't work, the language setting might be stored in the Steam emulator file. The reason this remains a community-driven "exclusive" fix
How to Change Language from Russian to English in Street Fighter X Tekken The reason this remains a community-driven "exclusive" fix
Some older Capcom PC titles tie their UI language to your Windows "Region" settings. Control Panel Administrative The reason this remains a community-driven "exclusive" fix