This is different for each company.  If you are getting a lot of customer support questions from a foreign market, then do your user materials and FAQ and other customer support content first. If you are getting lots of international web traffic, then look at translating your website. If you are heavily recruiting employees in other markets, or have a large staff there, then translate all your HR content. (Yes, recruiting content is marketing content).  If you are driving aggressive growth in a new market, then look at your top performing marketing content. Ultimately you have to spend your money wisely and that means it won’t be possible to localize it all, so always look at the data.