It's a versatile word used in different contexts. For example:
* "Rwy'n gallu siarad Cymraeg." This translates to "I can speak Welsh."
* "Does ganddi hi ddim gallu i wneud hynny." This translates to "She is not able to do that."
It's important to note that "gallu" is a verb, and it functions similar to the English modal verb "can."