Nowadays, they'd simply say that the Hols studied the Internet to learn about Earth culture, which is both more realistic (because if you were a member of an alien culture looking to assimilate, it would surely seem like the ideal tool for learning everything from the Britannica facts to the more colliquial stuff quickly and easily), and potentially more hilarious (because the Internet has a very Internet-centric view of how social interactions work, which could make people think that Katar and Shayera were, like, autistic /b/tards, constantly spouting memes in 1337-speak).