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It is not uncommon to see a toddler talking to themselves. Self-talk is so common that scientists have termed it a normal part of human language development. Research conducted by Erin Colbert-White, associate professor of psychology at the ��������, suggests a surprising parallel between self-talk and the self-directed vocalizations of a home-reared parrot.

The study, published in the International Journal of Comparative Psychology, compared self-directed vocalizations of a verbal two-year-old girl and a home-reared African parrot named Cosmo. The findings from the study, “Compositional differences, functional similarities: A linguistic analysis of private speech from a young child and a home-reared African Grey parrot,” challenge long-held assumptions about what makes human language so unique. Cosmo's human companion is Betty Jean Craige, professor emerita of Comparative Literature at the University of Georgia.

“Both subjects showed evidence of practicing new sounds, repeating words, and potentially using speech to self-soothe," Colbert-White said. “The structural differences were clear, but the functional similarities made us rethink some fundamental questions.”

Professor of Psychology, Tim Beyer, a specialist in human development, collaborated on the study, bringing his expertise on typical human language development. Professors Colbert-White and Beyer compared the self-vocalizations of a companion parrot with existing transcripts of a young child named Emily. These transcripts came from a database called CHILDES (Child Language Data Exchange System), which archives datasets of children’s speech.

Recent graduate Matthew Maus ’24 also played a role, helping to format the paper and managing citations.

“I really enjoyed my time working with Dr. Beyer and Dr. Colbert-White,” Maus said. “It was a great experience, both educationally and getting to learn more about such a fascinating thing, like the evolution of human [language]. I mean, who thinks of that?”

Maus shared that the project offered unexpected career benefits as the attention to detail required directly transfers to his current job as an employee experience specialist at a Minneapolis e-discovery firm.  

This research revealed several key findings. Both the parrot and the child participated in vocal play and repeated new words while alone. Emily's speech demonstrated more complex grammar and vocabulary, whereas the parrot produced sounds that facilitated practice, but used simpler vocabulary.

Beyer cautioned that Emily represents an unusual case as she’s “atypically advanced in her language use.” According to Beyer, most children don't have this level of verbal skill at two years old.

Colbert-White pointed out that the parrot appeared to be experimenting with sounds and words, as well as repeatedly practicing new vocabulary, which is similar to what human children do when they talk to themselves. In a separate but equally significant finding, the researchers observed patterns suggesting potential self-regulation through vocalization in both subjects. This led Colbert-White to ask the question: “If we're willing to say a child uses speech to self-soothe, when we find something similar in a parrot, are we as willing to say it could be this very subjective kind of personal experience?”

The study adds to growing evidence that some non-human animal species share cognitive strategies with humans, particularly among vocal learners like parrots.

“Understanding human communication requires looking at non-human animals too,” Beyer said. “It's not about who's 'better,' but about seeing human development as part of an evolutionary continuum.”

While limited to two subjects, the study opens doors for broader comparisons. Future research could explore other talking species or typical children’s private speech. For now, it’s a reminder: the more we listen, the more we discover how much we share with the rest of the living world.