All of theses programs will sharpen your skill with any language you want to study and learn. The key to progress though is reading in that language. Reading forms the foundation of your aptitude. Through reading you gain vocabulary, grammatical correctness and even some cultural literacy. Furthermore, reading allows you to pause and consider what you just read, to truly comprehend it. So, Rossetta stone or any other language learning program can help, but let reading in the language be where 75% of the learning takes place. All the best. Never quit you'll make it.