Language Evolution - Can a Word Imitate Shapes?

Linguists at the university of birmingham tested words in 25 different languages. Participants were told to look at two shapes and then listen to the sound either boba or kik. Then they were asked which shape corresponds to the sound. Most participants said the rounder shape was buba and the pointy one was keki. One possible explanation could be the appearance of the letters, the shape of b, o, u, b, a, rids.