We use language every day. From asking a stranger for directions to discussing a business transaction to professing love for someone in our lives, most of us need language to speak and be understood. For me it’s difficult to even fathom not being able to express my thoughts and desires to others. But where does language – this wonderful, practical gift – come from?

One interesting answer comes from MIT linguist Shigeru Miyagawa. As reported in Live Science, Miyagawa’s integration hypothesis puts forward the idea that human language is a synthesis of two systems that come to us from the animal kingdom. The first, called the expressive system, can be equated with grammar and is used by songbirds. Interestingly, songbirds sing for specific purposes, such as attracting mates, but their songs don’t have any specific meanings. (This does bear a striking resemblance to human tweets on Twitter, I think…) The second system, called the lexical system, can be equated to words and is used by monkeys. Using this special type of system, some monkeys are able to communicate which types of predators are threatening to attack, like an eagle, for example. But how did birdsong and monkey calls become human speech?

The integration hypothesis doesn’t exactly explain how these two systems merged to form human language. Frankly, I think that’s a pretty important piece of the puzzle. However, Miyagawa and other researchers plan to study other mammals that use expressive systems (since how birdsong influenced human language is a bigger mystery than how monkey calls could have).

Other linguists have criticized the integration hypothesis. Jim Hurford says it is “too simplistic.” William Croft questions the underpinning of the hypothesis – a theory from Noam Chomsky called Merge. But every idea has its detractors.

Whether the integration hypothesis is right or wrong though, it is most certainly an interesting one.