A muezzin is someone who issues the five daily calls to prayer in a mosque, a place of Muslim worship. The muezzin also issues the calls for Friday prayers. In Muslim communities, the voice of the muezzin is a familiar feature, floating out across the community five times a day from the mosque to remind faithful Muslims to cease their activities and pray. Daily prayers or salah are a very important part of Muslim faith.
The position of muezzin is ancient, with most historians believing that the role of a public crier probably pre-dates Islam. Many cultures have some sort of history of a public crier, usually chosen for his penetrating voice, who would have called out news and information of note in eras before other modes of communication. During the time of the Prophet Muhammad (peace be upon him), faithful followers of the Prophet would issue the call to prayer in the streets, laying the groundwork for the modern muezzin.
Mosques typically choose a muezzin on the basis of character and skill. A muezzin may become a respected member of the community, especially if the call to prayer or adhan is delivered particularly well, but he is not a religious official. The adhan is always issued in Arabic, and most Muslims are familiar with the words in the call to prayer, even if they do not know Arabic. In a mosque with a minaret, the adhan is called from the minaret, ensuring that it can be heard.
Traditional muezzins relied on acoustics and the strength of their voices to ensure that the call to prayer was heard by the faithful. Modern mosques use speakers to carry the call to prayer, ensuring that it can be heard at a great distance. In devout Muslim cities with multiple mosques, the call to prayer can get a bit chaotic, with dueling calls from multiple speakers around the city, and it is a feature of the Muslim world which is often noted by travelers.
While issuing the call to prayer, a muezzin faces the direction of Mecca, and he begins the call with the words Allah u akbar, meaning “God is great.” The adhan is quite melodious, and many Muslims find it very beautiful. In areas where no muezzin is present, the Muslim faithful are expected to remember the rhythms of the daily prayers on their own.
Incidentally, according to one Islamic myth, the muezzin also inspired the name of the Prophet's cat, Muezza. In the story, the Prophet was seated writing at a desk when he heard the call to prayer. When he rose to respond, he realized that his cat was asleep on his sleeve, and rather than disturb the cat, he cut his sleeve off so that he could rise to face Mecca.