It can also be used figuratively to mean "to exclaim" or "to announce loudly".
For example:
* "Fe wnaeth y plant gweiddi yn uchel" - The children shouted loudly.
* "Fe wnaeth y dyn gweiddi ei enw" - The man shouted his name.
* "Fe wnaeth y papur newydd gweiddi'r newyddion" - The newspaper announced the news loudly.