"I got a call from my mother but she did not say anything about it."
Translation:Fuair mé glaoch ó mo mháthair ach ní dúirt sí aon rud faoi.
Abair is one of six irregular verbs that uses ní rather than níor in the past tense. (The other five are bí, déan, faigh, feic, and téigh.)
Labhair is closer to “speaking” than “saying”. I think it would be at least awkward if not incorrect to use labhair in this example.