How to prove that papers were presented when conference programs are not in English?
Not everything on your CV needs to be verifiable via an Internet link. 

I have many items on my CV that would require some interaction with a human to verify: degrees I've earned, summer research students I've mentored, seminar talks I've given, classes I've taught, etc.

As long as you can, on demand, provide contact information for someone who can confirm your presentation (e.g. conference organizer), I don't see why this is a concern.

If you want to provide a link to the non-English conference program, go ahead; someone who is sufficiently motivated can surely get it translated.

(I'm sure this goes without saying, but since I've seen a shocking number of CVs that say "Presented at Conference X" without further information I'll say it anyways: you must include the full details of each presentation, including its title, co-authors if there were any, full name of conference, date, and city.)