"I teach Welsh in a school. I'm a teacher."

Translation: Dw i'n dysgu Cymraeg mewn ysgol. Athrawes dw i.

[Undolf]

What is the difference between using Dw i'n and Dw i? Similarly, the difference between dych chi'n and dych chi.

[MrGWallCymraeg]

The yn/'n introduced a verb, noun, or adjective :)

[EllisVaughan]

Without the "'n" the tense is unclear as from "Dw i/dych chi" you can then have "dw'n/dych chi'n" which is present tense, or "dw i wedi/dych chi wedi" which is past tense. The "'n" isn't needed in second sentence, but I'm not sure why sorry.