With Muslims coming to worship night after night during Ramadan, mosques aiming to enthrall their biggest crowds of the year look to one person in particular: their reciter.

His is the voice chanting the Koran, leading worshipers in prayer. And during the month of Ramadan, which begins at sunset Sunday, the special late-night prayers last two hours, which makes a beautiful singing voice and a powerful sense of soulfulness especially important.

The Koran emphasizes the value of a sweet voice, said Hatim Yousef, one of the reciters at the All Dulles Area Muslim Society (ADAMS) in Sterling, where 3,000 people come each night of Ramadan to the mosque’s seven branches.

“The Ramadan prayers are long, so it makes it that much nicer,” he said.

Even Muslims who tend to be less observant usually come to mosque at some point during Ramadan, a month when Islam teaches that the power of prayers and good deeds are amplified. It’s believed to be the time when the Koran was revealed. But many American Muslims don’t understand Arabic, and Islam teaches that the poem-like Koran is only truly understood in that language. So the reciter’s transmission is essential.

Hafiz Hatim Yousef teaches students at the Adams Center in Sterling, Va., how to memorize the Koran. (Katherine Frey/THE WASHINGTON POST)

In addition to reciters with a melodic voice, mosques also seek a hafiz, someone who has memorized much or all of the Koran. Because the American Muslim population is small and relatively new, many American mosques have to hire a hafiz for Ramadan from overseas or elsewhere in the United States.

But the Washington region has one of the largest Muslim populations in the country, and leaders have focused in recent years on producing homegrown spiritual leaders. Part of the drive to get U.S.-trained clergy, including Ramadan reciters, is because of tighter, post-Sept. 11 visa restrictions, local Muslim leaders said.

An increasing number of mosques that have in-house reciters are in the Washington area. Some are older Muslims who came back to study after establishing secular careers; others are U.S.-born youths who lead hundreds of people during Ramadan.

Yousef, 35, grew up studying Islam’s sacred music in Dubai and then English literature, focusing in graduate school on Welsh poet Dylan Thomas. Now, he leads some of the regular prayers during the year at ADAMS and teaches Koran at the mosque’s school.

Speaking in a soft, melodious voice, Yousef says his goal in leading prayer is for listeners to be engrossed in scripture.

“I feel success if people have more presence of prayer, if they are more connected to God, if they sort of don’t focus or don’t mention or think about anything but the Koran,” he said in the upstairs prayer hall, where his students sat on the green carpet before floor-to-ceiling windows, studying texts propped up before them on small wood stands.

One of his students, a 14-year-old who has become a hafiz, will sit beside him during the Ramadan prayers and follow along to correct him if he makes any errors. Yousef’s regular work schedule will be shorter during Ramadan so he can practice for reciting during the nightly prayers, which run from about 10 p.m. until midnight, after the daily fast is broken at sunset.

In the Middle East, Koran recitation is a profession, with people hired to sing at weddings and funerals. Here, most people have other careers.

The roles of all Islamic spiritual leaders are in huge flux in this country as a largely immigrant population builds uniquely American Muslim institutions. While mosques and imams in Muslim-majority countries tend to be about meeting people’s basic prayer needs, their counterparts here are just starting to look more like American churches or synagogues and offering more.

ADAMS, for example, now does a 10-minute lesson in the middle of each Ramadan night’s prayer, and during the year holds lectures and concerts of spiritual music.

New imam-training programs offer preaching, including the first accredited program in the country, at the International Institute of Islamic Thought in Herndon, which began last year and has a preaching course taught by an Episcopal priest.

But during Ramadan, the focus is on worship and, of course, the voice.

One of the world’s most famous Koran reciters will lead worship this month at the Islamic Center Northern Virginia in Fairfax. Sheikh Mohammad Alraee is in the area from Saudi Arabia to get his PhD in systems management, and for the last couple years has been leading Ramadan worship at the center.

“Once you listen to his voice, it’s a whole different spiritual experience,” said Muhammad Farooq, president of the mosque. Muslims aim to read the entire Koran during the month of Ramadan, and when Alraee gets to the end,Farooq said, “thousands of people are crying, listening to him.”