A TPRS teacher recently wrote:
I know we’re not about writing because it’s output but not input, but maybe this kind of thing would help the kids see the value in paying attention to those stories in class, and give them a chance to see that there are thousands of kids who are being taught this same way.

This is sort of scary to me. It’s certainly true that TPRS isn’t primarily about output. We do not believe that language proficiency is significantly advanced through output, and most of our class time is spent on input-based activities, or should be.

But that’s a little simplistic. TPRS isn’t anti-output by any means. TPRS is against output that’s too early, not all output. And output that’s too early means output before the language being output has been solidly acquired. Many times, we state this by saying that the language should “fall out of the mouth” or “off the pen” without effort.

Output has a lot of purposes: it builds confidence, it showcases success, it provides a medium for sharing and collaboration and community. It isn’t evil in and of itself. Output is only bad when it works against language acquisition. But output is only good when it involves language that has been thoroughly acquired.

Output that involves language that has not yet been acquired does not build confidence. It showcases errors instead of success, and it provides a medium for sharing mistakes and errors and incorrect language that becomes input for others.

So perhaps, in tandem with insisting on 100% comprehensible input, we need to be insisting on 100% acquired output as well as a condition of good TPRS practice.