Sure, ip geolocation is a very strong hint about what languge should be used. But being logged in and having set the language should override everything else, a

Sure, ip geolocation is a very strong hint about what languge should be used. But being logged in and having set the language should override everything else, and I don't see how a hypothetical shared computer scenario would change that. It's a shame that's not always the case on some Google sites, though you can usually work around it for a while by adding a hl=en URL parameter.