MKV is a container
A Matroska file can hold different tracks, including video, audio and subtitles. The Matroska specification describes those elements. The filename extension is not a quality grade and does not guarantee Hindi audio.
Codec support is separate
H.264 and HEVC/H.265 are video-compression formats. A player may recognise the container but lack support for something inside it. Renaming a file does not re-encode its video or create a missing sound track.
Read labels in the right order
First identify the title and year. Next consider the edition, language and completeness. Then look at source, resolution, codec and audio arrangement. A long string of technical labels should not obscure which movie you are opening.
Where this helps
If your own video file plays without sound, inspect the audio format and selected track. If subtitles are absent, check whether a track is embedded or expected separately. These are file-support questions, different from searching a catalog or an online service reporting that a film is unavailable.