Hatorade is still on S2 of the show, so I believe he is referring to Raven going from limping to normal level walking. It didn't heal, she just built/upgraded her leg brace to some crazy steampunk brace. It didn't get more than a throwaway line or two, but you can see it in some of the shots. In any case, her injury is an on-going plot point.
And I'm fine with the Grounder Language (although its only been a hundred years...you'd think English would still be the standard language); as popsicledeath mentioned its just a weird bastardized version of jive and ebonics. Silly, but it does get us awesome little things like the Ark survivors getting essentially named "Sky Crew". It sounds like a really terrible name for a street gang. Or worse, a break dance troupe. So bad that it crosses over to being amazing.
This season has been moderately disappointing so far, but that still puts it better than most other non-cable television. The City of Light storyline and the Polis politics have been pretty good, its just that the Pike and Friends plot is so goddamn bad that it is bleeding over to the other stuff. I think the Pike stuff would be watchable is we still had bloodthirsty Clarke around, at least then we could know that some shit was going to go down. But no one is here to watch Clarke suddenly grow a conscience.