If your target market is North America, then there's negligible motivation for going beyond Spanish and French as secondary languages.

French would only apply to a relatively small part of Canada; but it might spill over across the Atlantic, thereby giving your app an entrance into other parts of the world through social sharing.

Spanish is much more important -- not only because Spanish is used worldwide by a staggering number of people but also because Spanish is fast becoming a crucial second language here in the USA. Witness these statistics:

35 million Americans speak Spanish at home (2009)
76% of hispanic Americans speak Spanish at home (2009)
50.5 million hispanic Americans in 2010
16.3% of Americans in 2010 are hispanic
132.8 million hispanic Americans by 2050
30% of Americans by 2050 will be hispanic

Although few people listen to me, I always advocate for more attention to be paid to the Latino / Hispanic U.S. market. That's reflected in some of my own initiatives behind the scenes as well.

I don't necessarily recommend focusing on multilingual marketing right away. As others have advised, stick to the English-speaking audience initially. You'll have challenges enough early on without complicating matters by injecting translations and extra marketing channels into the agenda. English is your proof of concept, your test case. From there, expand.

That said, you should pay special attention now to how your brand name may facilitate or limit expansion into other language markets. All future possibilities should be taken into consideration at the moment of naming. That includes potential overseas marketing, the addition of new service / product offerings, and the very real possibility that you'll pivot and redefine yourself as something else -- foreseeable or unforeseen.

As a professional namer / domain investor, I'm not a localization consultant per se. But language factors into my daily routine. Last week, for instance, I wrote emails in Arabic and Spanish and had to fumble through a smattering of French, Italian, and Portuguese in my inbox. So maybe I can offer a useful perspective on your branding and marketing.