We prefer natural/conversational sentences. While phonetic diversity and different words in sentences is important, we are trying to make recording sentences as much fun as possible. Therefore it would be great if you could try to keep your sentences as natural/engaging as possible.
Mae'n well gennym frawddegau naturiol/sgwrsiol. Er bod amrywiaeth ffonetig a geiriau gwahanol mewn brawddegau yn bwysig, rydym yn ceisio gwneud recordio brawddegau yn gymaint o hwyl â phosibl. Felly byddai'n wych pe gallech chi geisio cadw'ch brawddegau mor naturiol/diddorol â phosibl.