The Azusa Street Revival was a historic series of revival meetings that took place in Los Angeles, California. It was led by William J. Seymour, an African-American preacher. The revival began on April 9, 1906, and continued until roughly 1915.

Speaking in tongues, also known as glossolalia, is an activity or practice in which people utter words or speech-like sounds, often thought by believers to be languages unknown to the speaker. One definition used by linguists is the fluid vocalizing of speech-like syllables that lack any readily comprehended meaning. In some cases, as part of religious practice, some believe it to be a divine language unknown to the speaker. Glossolalia is practiced in Pentecostal and charismatic Christianity, as well as in other religions.