Three language questions, three answers
The interface language tells you how the website is written. Original language describes the production. Audio and subtitle menus belong to the viewing edition. Flix2day uses an English interface and displays original-language information, but that is not a complete list of every translated track.
Culpa mía and My Fault identify the same Spanish film. Ni una más and Raising Voices identify the same series. Those alternate titles help with searching; they do not change which audio tracks a particular viewing service includes.
Make subtitles comfortable to read
Where the player allows it, adjust text size, contrast and background for the screen. A setting that works on a phone may be too small across a living room. Captions may include speaker and sound information in addition to dialogue, which can make them preferable for some viewers.
When the expected track is missing
Check the exact edition, season and device app. A dub can be available for one season but not another, or appear on one service and not another. Restarting a Flix2day search does not add a missing track to an external player.
Use original-language browsing to find productions, then compare the actual tracks after opening the viewing options. For anime, the anime guide also explains episode-order differences.