I took a half a year of French in grade school, a year and a half of Spanish, then GERMAN GERMAN GERMAN, and some Danish while I was at the Philipps-Uni. If I have it written out in front of me, I can puzzle out chunks of Romance languages based on my smattering of education and latinate roots for English words. If I sound out Dutch, I can follow it somewhat. I can sometimes get the gist of Danish/Swedish/Norwegian/Icelandic. I have provided rough translations of Anglo-Saxon law texts for my GF based on knowing German and English, and with a little help from a German university's online law library. But I wouldn't trust my translations, generally, and I find a lot of people don't see the same cognates I do just because their brains aren't wired. Much like understanding foreign phonemes, your brain might just not be "attuned" until you've had enough exposure.

Hell, on the topic of totally not hearing a phoneme, it wasn't till I took Linguistik at the P-U that I finally got what the difference was between English "sh" and German "sch", or how an umlaut really worked. I found out I'd just been faking it for 6 bloody years!