Some youths in Sweden are doing this in Swedish, being unable to properly communicate in their native language. Their English is usually not that great either though.
Some are foreigners, others are extreme nerds who have failed to interact with people and have lived on the internet.
Learning language is a lifelong journey, I'm convinced we continue to master our native language as well as we age. Maybe more so if we care and pay attention to it. So I hope there is still hope for some of the youth..
And I would add that I think becoming more than proficient in and deepening understanding of one's own language (Swedish in that case) is important, in parallel with learning foreign languages.
Some are foreigners, others are extreme nerds who have failed to interact with people and have lived on the internet.
It's really sad.