One of the most salient features of Matroska format is support for multiple tracks and embedded subtitles. MKV file containers are popular for distributing animated movies to give viewers the option to select their preferred audio or subtitle language version. For example, some users watch anime with original Japanese audio and English subtitles or in different language combination.
Each MKV file has a default track which is played automatically. MKV format does not limit the number of tracks that at single container can hold. A typical file witk MKV file extension contains more than one track. The more tracks a container stores, the larger its size. However, container size does not affect playback performance as tracks are not loaded into working memory.
Users have the option to change or disable tracks dynamically. It is considered a good practice to properly name subtitle tracks by adding language information. This prevents users form checking each track to find the language version they prefer.