It happened Friday at Irving's Lady Bird Johnson Middle School.
Video of the incident was sent to FOX 4 by someone inside the character-building assembly.
Two teachers, including second-year teacher Amber Collis, were playing a word association game.
Collis says "Fox," and the other unnamed teacher says "Courage."
As the crowd reacts, the other teacher playing the word game covers her mouth and walks away.
Collis takes the microphone from a man holding it and tries to quiet the crowd and get their attention.
The video then stops.
The students and staff were shocked and surprised by what they heard. The principal wasn't present at the character-building session, but the principal did meet with the staff afterward, and they talked about their feelings.
"During a seventh-grade assembly...a regrettable situation occurred....school and district officials do not condone or approve of such language...we can reassure our families that we have taken personnel action," a school district official said in a statement.
Staff members talked with students face-to-face after the incident, and the principal sent a letter to her staff saying that she would love for the incident to not have occurred. Now, the school must pull together in love, she says.
FOX 4 made several visits to the teacher's home hoping to give her the opportunity to explain, but we were not able to reach her on Wednesday.