Also read: things not to say, religion, Muslim, Islam, religious discrimination, Barack Obama

Editor's Note: This article was edited Aug. 20 to reflect the correct number of Muslims worldwide as an estimated 1.6 billion. Also, we have clarified the names and titles of the senior leaders in the U.S. government who are Muslim.

With Ramadan--the holiest month on the Islamic calendar--about to begin, issues of religious accommodation and cultural competency may come up in your workplace. That's because Islam is the fastest-growing religion in the United States. To help you avoid offending Muslim colleagues now and throughout the year, here are five things not to say.

For best practices and legal advice on religion in the workplace, check out our upcoming webinar on faith.

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1. "Why can't Muslims decide when Ramadan starts?"

Since the Islamic calendar is lunar, Ramadan is determined by the sighting of the new moon, which varies from year to year. And like other faiths, there are interpretational differences in beliefs. "In America, there are two groups of Muslims: The first believes you can use scientific data to determine when a new moon can be sighted, and thus you can predetermine the month," says Nadir Shirazi, creator of "The Ramadan Guide for the Workplace." The second group, he says, "believes that you must sight the new crescent moon with the naked eye." So the start/end dates of Ramadan, depending on the practices of Muslims in your workplace, may be different. This year, the holiday can start at sunset on the day proceeding Aug. 22 (or 23) and end Sept. 19 or 20 (or 21). Providing flexible hours and allowing floating holidays will permit employees of Islamic and other faiths to celebrate their holidays without using all their vacation time.

2. "Why can't you eat today?"

During the month of Ramadan, Muslims fast during daytime hours, so scheduling office parties, fall festivals and luncheon meetings at that time "puts a Muslim coworker on the spot [and] can be embarrassing for both parties," explains Shirazi.

Education and consideration are key. "The ideal thing is don't schedule office parties during these times," says Niham Awad, founding member of the Council on American-Islamic Relations, the nation's largest civil-liberties organization for American Muslims, based in Washington, D.C. "The least thing employers can do is don't force employees to attend these parties, with all the food and drink, while fasting."

3. "But you don't look/dress like a Muslim."

With an estimated 1.6 billion Muslims worldwide, to think all look and dress similarly is a stereotype. "All Muslims do not have long beards or wear white robes or hijabs," explains Imam Hamad Ahmad Chebli of the Islamic Society of Central Jersey (ISCJ), a nonprofit religious, charitable and educational organization in South Brunswick, N.J. "That's the image people see on CNN." In reality, Islam principle specifically states that there's no compulsion in faith. Conversely, asking a Muslim woman why she doesn't cover her body in a black niqab or drapery is equally inappropriate. "Islam is very much a personal and private religion," says Afia Mirza, a DiversityInc intern who is Muslim.

4. "I didn't know you were Arab."

This is another culturally insensitive comment. The reason: Only about 20 percent of Muslims worldwide are Middle Eastern. "Muslims are Black. Muslims are white. Muslims are senators … they're in the White House," says Chebli. (According to The Pew Forum on Religion and Public Life, three senior leaders in the U.S. government who are Muslim include: Dalia Mogahed, senior analyst and executive director of the Gallup Center for Muslim Studies; Ebrahim "Eboo" Patel, founder and executive director of Interfaith Youth Core [Mogahed and Patel are on the Advisory Council on Faith-Based and Neighborhood Partnerships]; and Rep. Keith Ellison, D-Minn.) According to the American Religious Identification Survey, 10 percent of Muslims are Latino, 15 percent are white, 27 percent are Black and 34 percent are Asian.

5. "Why can't you pray on your coffee break?"

Depending on the times allowed for office breaks, this comment can violate religious rights. That's because "Muslim prayer must be done within specific time frames," says Awad, adding that the second and third prayers are during business hours. What's more, Muslim prayer involves standing up and bowing on the floor, which can be awkward to perform in the workplace. It's also preferred that prayer be done in a group. Progressive companies will designate a private room or other facility for group prayer. On Fridays, when Muslims are obligated to pray in mosques and not in the office, "companies must give an extended lunch hour," explains Awad. Companies such as Ford Motor Co., No. 28 in The 2009 DiversityInc Top 50 Companies for Diversity®, are involving their interfaith-based employee-resource group to help give members space to share experiences and ideas of religious accommodation. "These are not only constitutional issues," says Awad, "but when you have a friendly work environment, you will have better performing and more loyal employees."

For more on how employee-resource groups can help your company, visit DiversityIncBestPractices.com.