Handbrake: foreign audio search or english subs or both?

Handbrake

For an English movie, I always want subtitles on - so would select
burned-in for the VOBSUB english - but do I need to also select 'foreign
audio search' (forced & burned) for the occasional foreign speech? So, do
both need to be selected, or will selecting 'English VOBSUB' cover all bases:
the english speaking and the foreign speaking.

If i select both, the occurrence of two identical subtitles on the screen at the same time would be annoying.

This is for a MKV that has both English VOBSUB and 'foreign
audio search'.

Thanks kindly for your help.