«The bouba/kiki effect is a non-arbitrary mapping between speech sounds and the visual shape of objects.

In 2001, Vilayanur S. Ramachandran and Edward Hubbard asked American college undergraduates and Tamil speakers in India "Which of these shapes is bouba and which is kiki?" In both groups, 95% to 98% selected the curvy shape as "bouba" and the jagged one as "kiki".»

12 new shapes for a linguistic experiment.