I have always crinched on these threads when I read "proven".... I was taught it should be "proved"... It grates on me almost as bad as "for free"... but according to some academicians... see below...
even the FR spell checker doesn't like "proven"..... but...
PAST PARTICIPLE
is the third principal part of an English verb. In weak verbs, the pattern is glide, glided, glided; in strong verbs the pattern varies in form: it can be unchanging, as in set, set, set; it can change vowels for past tense and past participle, as in swim, swam, swum; it can change vowels and add a final -n or -en for the past participle, as in fly, flew, flown and drive, drove, driven; or it can have various combinations of these three general patterns. The forms of strong verb past participles are often in divided usage (show, showed, showed or shown; prove, proved, proved or proven). 1
I was always taught that proved was correct but then had read proven was accepted. I think the dictionary people just give up sometimes when an unaccepted word overwhelms the accepted one. The same happens with pronounciation. The other day I mentioned that the word flaccid is pronounced flak-sid. It always had been one of the most frequently mispronounced words. Now it appears that the pronounciation flas-sid is becoming acceptable. Things change. Everything except the corruption in Durham.