I am dismayed by the seemingly endless number of onomatopoeic (or sound-symbolic) words in Japanese. I rarely have any idea of what these words mean from the sound, except maybe in the vaguest possible sense like "hard sound" versus "soft sound", but even that doesn't seem totally reliable. Usually I try to guess from the context, and then when I check the meaning I more or less instantly forget it, so next time I see the same word I can't remember. Do Japanese people have to learn all these words individually, or is there some instinctive understanding that native speakers acquire? Roughly how many of these words are there altogether? Is the number even fixed, or are new ones invented to order?