In a tournament environment, I tend to try my very best to not need a translation of the card. Since it is a competitive environment, players are expected to recognize the cards by the art. On the other hand, I still usually bring translations with me (folded text-in inside sleeves with my sideboard) for Opponents who find the alternate language distracting or confusing, such as new players or individuals with obvious problems maintaining focus/attention. I have even offered to supply my opponents with the applicable translation to my Tezzeret, Agent of Bolas, only to have them decline and then 2 turns later act dismayed that he was able to drain them for their last 10 life.
I choose not to put the translations in the sleeve with the card, as I've had terrible luck with frequent deck checks that I can only imagine were triggered by the number of foil cards I was fielding that day. I'd hate to lose a game due to providing my opponent with a courtesy.