Irish splits "to be" in two. Tá describes a state, a place or an action in progress - tá mé tuirseach. Is identifies or classifies - is múinteoir mé. Choosing the wrong one is not a small error; the sentence stops making sense.
Examples
- Tá mé tuirseach.
- I'm tired.
- Is múinteoir mé.
- I'm a teacher.
- Tá an lá go breá.
- The day is fine.
The mistake to avoid
Use is for who or what something IS, and tá for how or where it is.
Where this fits in
Numbers, days, time, Irish Gaelic A1: Count, talk about days and months, give the time, and handle numbers in real situations.