“Output is when students, or language learners actually use language to create a message of their own, from scratch.”

Yep, that would rule-out Sentence Frames (e.g. My favorite food is _____), and any other scaffolding when it comes time to creating a message. The result is “traditional language practice” which has not been shown to lead to acquisition. A single genuine utterance (e.g. “pizza”) as part of a communicative event (e.g. “Charles, what’s your favorite food?”) is more beneficial in the long run.

Interaction is NOT making students speak. 

Interaction is “2+ people demonstrating that they are involved in meaning making,” which might include speaking, but could just be facial/eye expression, nodding, and other gesturing. If you make students speak, you might get more of that “traditional language practice” that doesn’t lead to acquisition, and as most of us have experienced, you might also get one very anxious student who freezes up and feels silly amongst peers. That’s not good teaching.

Speaking is not necessarily Output.

Students can say things in the target language that are not messages of their own. Just saying things amounts to “traditional language practice” that doesn’t lead to acquisition.

“You make Output when you have to.”

This was in response to a question about whether or not students will be able to produce Output without interacting or “using” the language despite creating mental representation of (i.e. acquiring) a language. One CANNOT simply Output without mental representation, and if there is never a genuine NEED to Output, there’s no sense in all that “traditional language practice” that isn’t Output and doesn’t lead to acquisition anyway.

All of the work creating mental representation will pay-off, for example, when a student spends time in another country and uses the target language as part of a communicative event. In the case of Latin, there is a very high unlikelihood that students will ever have a genuine NEED to Output in Latin, so time is better spent developing mental representation in order to read fluently (speed + accuracy). The “traditional language practice” for Latin is typically translation skills, which have even less practicality than has been thought. After all, the few teachers and classicists who find themselves in Latin-speaking communities don’t even spend time translating with one another.