I wonder how did I manage to learn English without using any applications at all. Just these funny things they call 'pen', 'paper' and (OMG!) 'books'. And some tapes for pronounciation as well.
What on Earth is 'language teaching software'? Isn't it, like, sort of digital bullshit?
You guys have now what I didn't have when I was learning English - a huge amount of texts, videos and any kind of learning materials a man can imagine available from your web browser for free and an opportunity to talk to native speakers any time you want.
If you want to learn English - just go and learn bloody English full stop. If you just enjoy searching for any Linux/Windows/MacOS apps which would teach you... Well good luck then.
P.S. Where do I get Linux counterpart of that cool windows application which would enlarge my penis?