There is no single creator of the Welsh "not," as it evolved over centuries from Proto-Celtic roots.
Here's a breakdown:
* Proto-Celtic: The ancestor of Welsh had a negative particle, likely pronounced something like *ne*. This particle wasn't always directly attached to the verb.
* Early Welsh: This *ne* evolved into *ni*, and became more integrated into verb phrases.
* Modern Welsh: The "not" we see today, *ddim*, developed from a combination of *ni* and other elements. It's a complex process that involved grammatical changes and the influence of other languages.
Essentially, the Welsh "not" is a product of natural language evolution. It's not something one person invented; it's a gradual development that reflects the history of the Welsh language itself.