Good question, but my feeling is wrong time to ask it. It's hard enough to get users, period. Getting users in your home country is going to be much easier than a foreign country (I'm assuming you're a US based company/founders). Now, there is a time when I would absolutely look at language support for other countries, but there is so much to learn about your product, your users, your customer acquisition and all that jazz before you go and build out the code to handle different languages.

Now, if you are building a really basic app that is easy to translate, then maybe. But if the app is going to be a reasonably sophisticated social app, with at least a few bells and whistles, it may be more than you want to take on at first.