* No written records: The Stone Age predates written language. The oldest known written records are from around 3200 BCE, well after the Stone Age ended.
* Language is spoken: Spoken languages leave no physical trace.
* Evolution of language: Languages are constantly evolving. The languages spoken in the Stone Age would have been very different from any languages spoken today.
What we *can* infer:
* Early languages were likely simpler: They probably had smaller vocabularies and simpler grammatical structures than modern languages.
* Proto-languages: Linguists have reconstructed some very early languages (called "proto-languages") by studying the relationships between modern languages. For example, there was likely a "Proto-Indo-European" language spoken in Europe and Asia thousands of years ago.
* Sign language: Some researchers believe that early humans may have communicated using sign language before the development of spoken language.
In short, we can't say for certain what languages were spoken in the Stone Age. But we can make educated guesses based on what we know about language evolution and the archaeological evidence.