The filename terminator-genisys-2015-720p-dual-audio-hin-eng-www-7starhd-tours-mkv contains several key details:
: Within MKVToolNix, you can set the "Default track" flag to "Yes" for your preferred language so it always starts automatically [1.4.4].
: The file contains two separate audio tracks: Hindi and English.
If you want to permanently change which language plays first or remove one track to save space: