Birdsong as a musical proto-language
I argue that birdsong can serve as a parallel model with which to compare human speech to advance our understanding in the evolution of language, in a limited sense that birdsong has features to be regarded as musical proto-language. Birdsong is a long utterance consists of multiple notes organized into certain sequence. Songbirds use songs mostly in mating contexts such as territorial defense or mate attraction. In this sense, birdsong satisfies the first condition of musical proto-language. In the second step, musical proto-language should allow segmentation so that parts of it are associated with specific meanings. During the process of song acquisition, Bengalese finches segment and splice song chunks from multiple tutors and this learning strategy satisfies a part of the second condition. Furthermore, we found another parallel between song learning in birds and speech acquisition in human children: when learning a longer sequence both birds and humans proceed in bi-gram base, extending the sequence step by step. In accordance with these behavioral parallels, brain structures involved in song and speech acquisition show convergent evolution in birds and humans, and mirror neuron system combining perception and motor controls are found in both birds and humans. Taken together, I suggest birdsong can serve as a parallel model at least up to the babbling stage of human speech development.

BIO
Born in 1959 in Tochigi, Japan. Graduated from Keio University majoring in Psychology, and obtained a Ph.D. from University of Maryland (USA) in Bioacoustics. After working at several research institutes including Chiba University and Riken Brain Science Institute, I was appointed as a Professor in Cognitive and Behavioral Sciences, the University of Tokyo since 2010.

Website
http://www.brain.riken.jp/en/faculty/details/71
 

Background reading
http://www.nature.com/nature/journal/v498/n7452/full/nature12173.html
http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0310.2010.01772.x/full
http://link.springer.com/article/10.1007/s10071-011-0462-x
http://link.springer.com/article/10.1007/s10071-009-0302-4