Irish what does that mean? mo milis cailin, is doigh liom ta tu go deas.."?

Answer 1

The sentence structure and the grammar is not right and should read ' Mo chailín milis, is doigh liom go bhfuil tú go deas.
In Irish, the adjective (milis) follows the noun (cailín) and the dependent case of the verb (tá) (bhfuil) should be used.

It is an attempt to say 'My sweet girl, I think you are nice.'

Answer 2

My sweet girl, I think that you are nice - Pronounced "Muh meel-yush coll-een, us doh-ee luhm tah too guh jass (or dyass - in some dialects).