Well, I looked at the summary, and they're implementing a Seq2Seq model for this. It is what I think of as an archetype for machine translation and chat bot tasks.

Quite a few new network architectures in this space have been updates to this model, which uses an RNN encoder and a decoder, along with attention between them and a beam search for better results.

I wouldn't call this model a solution for natural language translation, nor would anyone else. But I think fast.ai meant that they're going to explain and go through this model, and how it's helped bring a new generation of models with good performance in this particular space.