Such is the case of Nike’s “Just Do It” campaign and the “Got Milk” commercials. In the last example the literal translation into Spanish would send a completely different message and a quite offensive one, and therefore the translated tagline is Toma Leche. (Drink Milk). There are countless examples of how many of these taglines do not only get butchered but truly get lost in the translation process and for those there are plenty of blog posts on that subject. It is then that companies decide to stick to the original and only translated the copy of the ad alone.
The first time I translated an ad I came up with 3 or 4 versions of the translated slogan and as I translated the rest of the copy, I submitted what seemed to me the most appropriate. Generally though they tend to be either too literal (which they complained about) or told me that I had missed the idea completely. So therefore I generally submit them all and have the client decide. It is for this reason that companies then in order to avoid confusion do tend to leave the original slogan. Given that in advertising the use of play on words, double meanings and puns are highly used, it becomes extremely difficult to recreate and culturally adapt these taglines. One truly does have to put a creative cap on this one!