In anglophone North America the ah-men pronunciation is used in performances of classical music, in churches with more formalized rituals and liturgy and in liberal to mainline Protestant denominations, as well as almost every Jewish congregation, in line with modern Hebrew pronunciation.
In Arabic the pronunciation ah-meen (ʾĀmīn) is used upon completing a supplication to God or when concluding recitation of the first surah Al Fatiha in prayer.