NYT is trying to make money
itunes.apple.com
itunes.apple.com
I suspect there is quite a market for this, actually.
Take my money. please.
And if someone can learn a new language more easily with it, it has life-changing potential (I know that learning English changed my life, and I would have loved to have this back then).
I would suggest reading some Jules Verne! You can find full texts of his stories online in French and English, and reading them in parallel (with the English as a check on your comprehension) will help you hoover up a lot of vocabulary while enjoying a fun story.
Japanese publishers sold hundreds of millions of dollars worth of "Learn English with Barack Obama" by taking his most famous speeches and annotating them. Yes, I think there is a wee bit of a market for selling practical English instruction to high-brow consumers in other nations. (Granted, a lot of people buying those books are paying for the experience of buying the book rather than paying to learn English, but that is true of plenty of software, too.)