* No written record: Spoken language predates writing by thousands of years. There's no way to directly observe or document its origin.
* Gradual evolution: Language didn't suddenly appear. It evolved gradually over a long period, starting with basic communication sounds and gestures, becoming more complex and sophisticated.
* No single "invention": Language isn't an invention like a tool. It emerged as a natural consequence of the human brain's ability to process and communicate information.
Instead of a specific year, scientists theorize about the timeframe:
* Origins of language likely began around 100,000-200,000 years ago, coinciding with the emergence of modern humans.
* Evidence suggests complex language, resembling modern languages, existed around 50,000 years ago. This is based on archaeological discoveries and the evolution of the human brain.
In essence, spoken language was a long and gradual process, making it impossible to assign a definitive BC year.