Computer languages are another story. Small vocab, tight syntax - you hardly need to learn anything at all
or for German You might say that a grammatical construct following the rules is rather the exception. I recommend a vacation abroad. In my experience that's the best and fastest way to learn a language. Avoid the tourist season and go abroad when you can be sure to be the only one from your country. Or go to some place that's far away from the classical holiday destinations. This way you'll hear the foreign language spoken around you all day and automatically pick up a lot of useful phrases. After only 2 days in Cardiff I automatically said "diolch" to the driver when getting off the bus, on day #5 I was invited to join a jam session with local musicians in a pub. And after only 10 days on Ischia I was able to chat a bit with the locals and even swap gardening tips. =) Learning by doing always works best