Human language builds on birdsong and speech forms of other primates, researchers hypothesize in new research. From birds, the researchers say, we derived the melodic part of our language, and from other primates, the pragmatic, content-carrying parts of speech. Sometime within the last 100,000 years, those capacities fused into roughly the form of human language that we know today.
The expressive layer and lexical layer have antecedents, the researchers believe, in the languages of birds and other mammals, respectively. For instance, in another paper published last year, Miyagawa, Berwick, and Okanoya presented a broader case for the connection between the expressive layer of human language and birdsong, including similarities in melody and range of beat patterns.
Birds, however, have a limited number of melodies they can sing or recombine, and nonhuman primates have a limited number of sounds they make with particular meanings. That would seem to present a challenge to the idea that human language could have derived from those modes of communication, given the seemingly infinite expression possibilities of humans.
- Shigeru Miyagawa, Shiro Ojima, Robert C. Berwick, Kazuo Okanoya. The integration hypothesis of human language evolution and the nature of contemporary languages. Frontiers in Psychology, 2014; 5 DOI:10.3389/fpsyg.2014.00564