[lillesvin]

I obviously don't know your background but out of the linguists that I know and have met while doing my degrees in linguistics, I don't know of anyone who would say that the kiki-bouba effect is not important — anything, in fact, that challenges the notion that sound-meaning relations are completely arbitrary is interesting because it might give us clues about the origins of language, not to mention that it lends support to other, related hypotheses about sound-symbolism.

I'm not sure what you mean by "not necessary parts of language", but I would love to hear what you think the necessary parts of language are. Not to mention, what is "the difficult part of language" then?

[suddenlybananas]

The Bouba kiki effect doesn't challenge the arbitrariness of the sign because arbitrary doesn't mean uniformly distributed. The effect shows that there's a preference between the two but it doesn't contradict the fact that either could be a perfectly fine label.

The difficult part of language is the fact we can build entirely novel meanings out of a relatively small finite set of words. Bouba kiki has no bearing on the way words are composed.

[lillesvin]

> The difficult part of language is the fact we can build entirely novel meanings out of a relatively small finite set of words.

So are you saying that we've got e.g. neurolinguistics, psycholinguistics, language acquisition and typology down? Or do you simply mean "interesting to you" when you say "difficult"? Because in my experience, pretty much every subject in linguistics (and most other sciences) is easy if you don't understand it and surprisingly difficult once you start to get a grasp of it.

> Bouba kiki has no bearing on the way words are composed.

It literally shows a preference best described by sound-symbolism so it most certainly has a bearing on how words are composed. Just because the relation between sound and meaning _can_ be arbitrary, showing that in some cases it's not entirely so is extremely valuable for evolutionary linguistics.