A “student” account is the default account type at Duolingo.
Source: https://support.duolingo.com/hc/en-us/articles/115000035143-What-is-the-difference-between-a-student-and-a-teacher-account-
If a language course has speaking exercises, then the students in a classroom have this feature too.

Help texts: microphone and sound

• https://support.duolingo.com/hc/en-us/articles/204642264-My-microphone-is-not-working-How-can-I-fix-it-
• https://support.duolingo.com/hc/en-us/articles/204882510-My-sound-is-not-working-What-can-I-do-

Help texts: Duolingo for schools

• https://support.duolingo.com/hc/en-us/categories/202010963-About-Duolingo-for-Schools