Seo is used with the third person singular or plural personal pronoun as described in Ó Dónaill (e) (With 3 sg. or pl. pers. pron.) Tá sé ~ ag imeacht, this person is leaving. Is é ~ mo pheannsa, this is my pen. An iad ~ do chlannsa? Are these your children? Tá sí ~ le pósadh, this girl is getting married. Más í ~ an iníon is óige aige, if this is his youngest daughter. Cad é ~ a dúirt sé? What is this he said?
Seo = this, sin = that. (Sin is pronounced shin)
Cé hé sin amuigh
A bhfuil faobhar ar a ghuth
These are the first two lines of a poem Éamon a' Chnoic.
Who is that outside
Who has an edge to his voice