Sound words can't be understood through formal study of the language alone. They're felt when you immerse yourself in the culture or lifestyle that becomes a part of you. The Japanese language is abundant with onomatopoeia. Even though I've lived in Japan a long time, sound words are still an uncertain territory. And I think new words are being created every day. Even when I don't know a word I can sometimes connect it to a meaning using the sensations produced by the sounds, which feels like I'm playing with words.