I like it (the web site and the "feel" of the product-- didn't try the product, but I'd like to).

I'd get a copywriter to review your site (one who specializes in persuasive writing for the web). The value prop is clear, but if you're selling language, you ought to nail your message. Phrases like "quickly gain thousand+ words", "ingolingo is the steroid of learning language", and "When he's not practising martial arts, he's at a social event talking with other clever people" are awkward.

While I like it, the design feels a tad soft/feminine (why the flowers?) - what are the demographics of people who want to learn new languages? Might be interesting to ponder color psychology... Is the design/color selection based off of what you guys like? Or what the target audience will respond to? I dunno the right answer, but it's worth pondering.

Out of curiosity, why isn't the app web-based? You probably have access to these stats, but I'd be interested in how many referrers you got from YCNews and what percentage of them downloaded your app and tried it? I bet that percentage would double if it was web-based.

It's nitpicky, but I'd adjust your brown link color in the footer... Hard to recognize as a link.