Bitesized Languages is not available for subscription via the Kindle, but then, it doesn't really need to be. You can subscribe to it for free and have it delivered to your mailbox.
All it is is one sentence a day, translated into English and... whatever language you've chosen. I've chosen Spanish and German (I get two separate emails.) The sentence is the same in both languages, so I"m learning both languages simultaneously, which is fun.
It's a lot easier to learn to read a language than it is to speak it. If you just want to be able to read books in the original, check out Bitesized Languages as a teaching aid.