Homo habilis likely communicated using a combination of vocalizations and gestures. While we do not have direct evidence of their spoken language, it is believed that they had a capacity for more complex communication than their predecessors due to significant developments in their brain size and structure.
This early human species may have utilized simple sounds or calls to convey emotions or alert others to danger. Additionally, they likely used body language and facial expressions, which are fundamental aspects of non-verbal communication. The use of tools and social cooperation indicates that they needed some form of communication to collaborate effectively while hunting and gathering food.
Over time, as their cognitive abilities evolved, it is reasonable to assume that their communication methods became more sophisticated, laying the groundwork for the complex languages we see in later human species.