.mkv editing help

what is a program i can edit a .mkv file?

I have some videos that have japanese and english as a audio..plus english subtitles. but i want to delete the japanese audio.

reason why i want to do this is to see if that will help with the video skipping. unless theres something else i can do. When i play videos that have several languages in the file the video lags.

any program that will work on mac os x.

 

MKVToolnix
With MKVExtract you can extract the streams of an MKV file, as for example the subtitles.

 

that program seems to not be supported anymore for macs...

is there any program that i can convert these mkv files to avi or something else? and still have it in english? since its in english and japanese.