The linguistic capacity to express and comprehend an unlimited number of ideas when combining a limited number of elements has only been observed in humans. Nevertheless, research has not fully identified the components of language that make it uniquely human and that allow infants to grasp the complexity of linguistic structure in an apparently effortless manner. Research on comparative cognition suggests humans and other species share powerful learning mechanisms and basic perceptual abilities we use for language processing. But humans display remarkable linguistic abilities that other animals do not possess. Understanding the interplay between general mechanisms shared across species and more specialized ones dedicated to the speech signal is at the heart of current debates in human language acquisition. This is a highly relevant issue for researchers in the fields of Psychology, Linguistics, Biology, Philosophy and Cognitive Neuroscience. By conducting experiments across several populations (human adults and infants) and species (human and nonhuman animals), and using a wide array of experimental techniques, the present proposal hopes to shed some light on the origins of shared biological constraints that guide more specialized mechanisms in the search for linguistic structure. More specifically, we hope to understand how general perceptual and cognitive mechanisms likely present in other animals constrain the way humans tackle the task of language acquisition. Our hypothesis is that differences between humans and other species are not the result of humans being able to process increasingly complex structures that are the hallmark of language. Rather, differences might be due to humans and other animals focusing on different cues present in the signal to extract relevant information. This research will hint at what is uniquely human and what is shared across different animals species.