I happened to see an article on Bouba/Kiki effect. Basically researchers show people two geometric shapes, and want them to guess which shape is Bouba and which shape is Kiki.  You can see two exemplary shapes on the right. Btw, which one do you think is Bouba?

Majority of humans choose the shape with many corners (jagged, the left one) to be Kiki, and the other to be Bouba, suggesting that the human brain is somehow able to extract abstract properties from the shapes and sounds[read the article].

This reminded me my ill founded hypothesis about the number 4. My native language is Turkish, and I know English. In the past I have tried to learn Arabic, Dutch, German, Russian and French. Right now I am living in Italy and learning Italian.

As you somehow always learn the numbers in a foreign language first, I noticed that in all languages the number 4 had an ‘r’ letter in it; dört, çar, četyre(четыре) , four, vier, vier, quatre, quattro, arba(أربعة) and so on.  My hypothesis was that all languages had a letter ‘r’ in number 4.


Bouba/Kiki effect can be seen here. Four, I think, reminds a shape with sharp four edges, and it is fairly reasonable to say that except three and four, we cannot really associate shapes with numbers.  How does a figure with 6 edges look like? Or seven?

After I started talking about this,  a friend told me about an egzotic language which did not have ‘r’ in number 4.

Interestingly, for the Bouba/Kiki effect, majority does not mean all of the humans. Around 3% of them still chose Bouba for the Jagged shape. So I guess some exceptional languages may have no ‘r’s in number 4. It would be interesting to learn if they have some common properties.  By the way, that friend was from Mahabharat of several hundred languages.

I used Google translate to see which languages do not have ‘r’. Here are some; Finnish, Basque, Chinese. I am sure the list is long.