It is a fairly universal saying, so much so that you did not need to translate it because it is already a common saying in English. If you are interested; It comes from looking in a horse's mouth is one of the only ways to determine age, by the wear on the teeth, and other general health indicators. So if one were buying a horse, you would always look at its teeth much the same way you would check under the hood of a car before you buy it. So yea, it is basically saying "dont assess the quality of a gift". Though I always wondered if it might have a more cynical meaning of "if someone gives you a horse, there is probably something wrong with it so don't check its teeth because you probably wont like what you find".Lets see how the Game is without Paying a cent for it. You always view something different when you either payed for it or got it free. Maybe for us its a good Game for 40 Minutes but for someone who payed for it not. In Germany they have a saying that is pretty nice. It goes like this: Einem Geschenken Gaul schaut man nicht ins Maul. Which Translates to, you dont look a Gifted Horse in the Mouth, which i guess means, its free be Happy or something HAHAHA