The spelling of the acronym "AIB" is quite straightforward. It consists of three letters, each pronounced separately. "A" is pronounced as "eɪ", which is a long vowel sound. "I" is pronounced as "aɪ", which is a diphthong. Finally, "B" is pronounced as "bi", which is a short vowel sound. When pronounced together, the word sounds like "ey-ai-bee". "AIB" stands for Allied Irish Banks and is one of the largest banking institutions in Ireland.