Since this is a "Dual Audio" file, it may start in the default language (often Hindi in these releases). To switch:
A group of elite mercenaries is tasked with overthrowing a South American dictator, only to find they are being used as pawns in a larger game involving an ex-CIA agent. The.Expendables.1.(2010).1080p.Dual.Audio.(Hin-Eng).mkv
Right-click the video while it's playing → Audio → Audio Track → Select Track 1 or Track 2 . Since this is a "Dual Audio" file, it