Next on my pile of books to read is “The Information”, by James Gleick, a birthday present from my brother. The first chapter talks about African talking drums, which were once used to transmit messages from village to village, enabling them to travel much faster than other methods of communication available at the time.
Many African languages are tonal. That is, the meaning of a word depends not only on the vowels and consonants in it but also on the pitch used when speaking it. Talking drums mimic the prosody of human speech – the pitch rhythm and volume – but cannot capture the sounds of individual letters. Thus, a lot of context is needed to disambiguate words. According to Wikipedia, the word “moon” is rendered as “moon look upon earth“, and the phrase “come back home” as “make your feet come back the way they went, make your legs come back the way they went, plant your feet and your legs below, in the village which belongs to us“. This use of context is similar to modern error checking codes that are used when sending messages over noisy channels.
Despite the huge amount of additional context needed, sending a message by drum only took about 8 times longer than speaking it. And the distance a drum sound can travel, 4-5 miles, made them a very effective form of communication.