§ 647. The difference in meaning between is and atá is well illustrated in the two familiar idiomatic Gaelic phrases corresponding to the English verbs "have" and "own".
We have no modern Irish verb for the Irish verb for the English "have" so we use the phrase "there is at;", thus, "Cormac has a ship" is translated by "there is a ship at Cormac", atá long ag Cormac. Here atá simply means that the ship is in Cormac's possession at the present time, implying conditions.
§ 648. Then take the verb "to own" a thing. We do not use any special verb to convey this idea in modern Gaelic. "Cormac owns a ship" or "ths ship is Cormac's" is translated by "the ship is with Cormac". Here is with has an idea of being permanently connected with, as a thing is with its owner, so the verb used is is, not atá. We say, therefore, is le COrmac an long. Note the order of the words.
§ 649. The words agam, agat, aige, aici, agaiḃ, aca, are already known to the student = at me, thee, him, her, us, you, them.
Liom, leat, leis, linn, with me, thee, him; as, léiṫi (lae'-hĕ) or léi, with her; liḃ (liv), with you; leo (lō), with them.
as in English