Here, "a" is pronounced as [eɪ]. But I thought pronouncing "a" as [ə] is more common. Is it just this person's unusual pronunciation, or should I use both pronunciation according to the situation?
The indefinite article ”a” is routinely pronounced 2 ways by native English speakers. It is usually pronounced as "ə" aka “uh” or soft a. But it is also regularly pronounced as "eɪ" as in A B C D … which is a hard A. Sometimes this difference is a choice made for emphasis. Ex: A. Where are you staying in the city? B. I’m going to stay at ə hotel” (any hotel) A. Are you staying at the Ritz? B. Well, I’m going to stay at eɪ hotel, but probably not the Ritz. The second is emphasizing the indefinite article - *a* hotel as opposed to *that* hotel. Other times the difference is simply because of the accent, region, or simply personal speech patterns. In general, the ə is more common, but that shouldn’t be taken to mean it’s more correct in all circumstances.