If a female teacher teaches male children who have learning problems through singing songs etc, at what age child is there an issue of kol isha? What happens if a non jewish janitor walks into class can the teacher continue to sing the children song or does she need to stop?
Concerning children, the issue of kol isha begins at nine years old (some maintain that it would begin earlier, but one may rely on this opinion for the purpose of children with learning problems). Provided he isn’t Jewish, there is no need to stop singing when the janitor walks past or into the class.
Sources: See Avnei Yashfei (Vol. 2, no. 5, sec. 6); Rivevos Efraim (Vol. 5, no. 491).