"Chan e taigh-bìdh a th' ann. 'S e taigh-òsta a th' ann."
Translation:It is not a restaurant. It is a hotel.
Originally it should, as a French import, but contemporary English has moved away from using "an" to accepting "a". However, see Fowler's Modern English Usage for much more light on the whole question (3rd edition 1996 ed. Burchfield) under 'a, an 3'). The best place to turn for help on what is good English, and what is half-learned in school but not the whole picture. It also reflects how our language has changed and is still changing.