"Madainn mhath Eilidh."
Translation:Good morning, Eilidh.
'math' changes to 'mhath' to agree with the feminine noun 'madainn'.
For whereas, in French you add an '-e' suffix to the end of a word to make an adjective feminine, Gaelic adds a change at the start:
math –> mhath, mòr –> mhòr, beag –> bheag
(Be careful, this change only happens to certain adjectives, NOT ALL! You will learn which ones change as you go along)