Spoken and Written Welsh

Three registers. A register is a style of language for a setting, like the difference between chatting with a friend and writing a report.

• Spoken: Dw i'n mynd, Ges i ginio, Bydda i'n hwyr, O'n i'n gweithio
• Standard written: Rydw i'n mynd (or Rwy'n mynd), Cefais i ginio, Byddaf i'n hwyr, Roeddwn i'n gweithio
• Literary: Yr wyf yn mynd, Cefais ginio, Byddaf yn hwyr, Yr oeddwn yn gweithio

What changes.

• Forms of bod get shorter in speech: yr ydwyf → rydw i → dw i. See Fuller Present Forms and Literary Forms of Bod.
• Verb endings and pronouns: speech says ges i, standard writing cefais i, and literary Welsh usually drops the pronoun: cefais. See Literary Past Endings.
• Negatives: speech puts ddim, or a word like neb, after the subject (Welais i neb, Wn i ddim); literary Welsh uses ni and no ddim (Ni welais neb, Ni wn). See Literary Negation.
• Particles: speech often drops mi, fe and the question word a but keeps their mutation (Welaist ti?); literary Welsh writes them (A welaist ti?).
• Regional words: speech has forms like isio (North) and moyn (South), while writing uses eisiau.

Which should I use? Speak the spoken forms of your area; Northern and Southern forms are both correct (North and South Welsh). Write emails and reports in standard written Welsh. Recognise literary forms when you read older books, hymns, the Bible and formal notices; you do not need to speak them. Many modern texts sit between these styles, and that is normal.