I think the key point here is that I'm not trying to learn Ruby. We're trying to get a single project done in Ruby. I'm the best person to do the project, Ruby is the best language to do it in, but I don't know Ruby.

If I was trying to learn Ruby, this is not the way I'd do it, and I'd go up the learning curve as normal, writing all those shitty PRs and making all the mistakes as normal. As you say, there are no shortcuts to achieving understanding.