^i imagine that it depends on which publication office you work at...like if you were working at vogue italia then you'd probably need to know italian, if vogue paris then french...so on. but at 'english-speaking' publications it's probably not required but it may come in handy from time to time.
however i have never worked at a magazine, this is just my own personal speculation so maybe some of the others with magazine experience can help you out
