When did Welsh language begin?

The exact origins of the Welsh language are not fully known, but it is believed to have developed from a Celtic language spoken by the ancient Britons who inhabited Great Britain before the Roman invasion. These Britons were part of the larger Celtic population that spread across much of Europe during the Iron Age.

Over time, the Celtic languages spoken in Britain diverged from each other, giving rise to the distinct Welsh, Cornish, and Breton languages. The earliest written evidence of the Welsh language dates back to the 6th century AD, but the language itself is thought to have been spoken for much longer.