Final answer:
We don't know exactly how language evolved with early hominins due to a lack of direct evidence, making it one of the hardest problems in science. Cognitive capabilities linked to tool-making could suggest a blueprint for language development, and the cooperation facilitated by language likely played a crucial role in human societal evolution.
Step-by-step explanation:
The question as to why we don't know how language evolved along with early hominins is rooted in the complexities of archaeological and linguistic evidence. We lack direct empirical evidence such as preserved speech or language patterns. However, archaeological records, such as the tool technologies of Homo habilis and Homo erectus, indicate that the cognitive and social capabilities required for tool creation could be analogous to those needed for language development. Advanced cognitive planning, necessary for tool-making, might have also played a significant role in the evolution of complex speech.Nevertheless, scholars remain divided as the overall absence of concrete evidence makes it difficult to pinpoint the exact origins and sequences of language development in hominin history. The origin of language poses one of the hardest problems in science, and despite new methodologies and theories, we have yet to reach a definitive understanding of how language came to be.