There is no indication how this word is used - would it be used for example in the sentence 'Dw i'n ysgrifennu tua Gareth' or would 'about' in that case be 'am'?
The other pasts of this lesson give some examples of how tua is used with the meaning 'about' a distance:
- tua milltir - about/roughly a mile
It can also be used with time:
- Mae hi tua deg o'r gloch - It's about ten o'clock
Yes, to talk about, write about, complain about, we use am:
- Roeddwn i'n siarad â Siân am Gareth ddoe - I was talking to Siân about Gareth yesterday
- Fe wnes i ysgrifennu llythyr at y cyngor am y ffordd leol - I wrote to the council about the local road.