bouncing

I went to Kyiv on business a few times around 10 years ago. It surprised me that most people in the office spoke Russian to each other, even though I don't think there were any Russians in the office and only a few non-Ukrainians. They would even comment on certain people insisting on using Ukrainian as if it was something weird. Unsurprisingly, nowadays the Ukrainians I know seem much keener to use the Ukrainian language.

Public nudity is generally legal anywhere in Spain, although in Barcelona and a few other tourist hotspots it is illegal to be naked or almost naked (i.e. in swimwear) in public places away from beaches etc. This only applies to public spaces (it was enacted due to tourists wandering the city streets and trying to enter shops, restaurants etc in swimwear and annoying the locals) but I suspect Martina doesn't want to be naked in full view of the neighbours.

I think it's Chondromalacia Patellae

They keep mentioning "cartílago" (cartilage)

I think it's medical results - that would explain the letter and DVD, and I think I caught some medical type words in their conversation (I generally think my Spanish is pretty good, but I really struggle to understand these two. I'm used to Argentine Spanish though, which has a very different sound).