A specific test
A useful experiment: have a student practise with their favourite AI tutor for 10 minutes, then pair them with a classmate who has been instructed to be slightly chaotic in conversation (changing topics, asking unexpected questions, going on tangents, occasionally not answering directly).
The student's performance in the two conversations will be measurably different. The AI conversation will look more fluent on the surface (smoother turns, fewer pauses). The classmate conversation will be messier - more hesitations, more clarification requests, more repairs.
The classmate conversation is the one closer to real-world fluency. The AI conversation is the practised script. Students who only train against AI develop fluency at the AI conversation and not at the messy human one.
What real classrooms add
A class of real students provides predictability-shock at no extra cost. The pair-work conversation is going to:
- Drift off-topic regularly.
- Hit vocabulary gaps the AI would have smoothed over.
- Misunderstand each other (both students might be reaching for half-known structures).
- Develop personal jokes and references that an outside listener wouldn't follow.
- Include the random energy of two human personalities interacting.
Every one of these is a feature, not a bug. Students train the repair skill, the tangent-handling skill, the cultural-reference-bridging skill - all of which they will use in real conversations and will never use against an AI tutor.
You can engineer this productively. Use the Team Maker to vary pair compositions across rounds (different partners stress different aspects of the unpredictability skill). Use the Topic Generator to pull in topics students don't expect. Use the Classroom Timer to add the time-pressure that real conversations have.
The point is not to be cruel about it. The point is to expose students to enough variability during practice that the real-world version isn't a shock. This is the same exposure logic as the accent variety argument and the slang and idiom argument - real classrooms provide breadth that AI tutors structurally can't.