#also just the idea of hiccup picking up dragon-like behaviors in general is amazing

[saturnniidae]

I don't think Hiccup can actually fully understand dragons (they don't really have a clear, learnable language. mainly communication through a range of sounds and body language), but his familiarity with Toothless' noises and mannerisms, and Hiccup's habit of mimicking them, has helped him understand the gist of what most dragons are trying to communicate and he often responds in kind. Sometimes he doesn't even realize when he's doing it and wonders why people are giving him such strange looks.