Write a language tutorial

We've had a language tutorial a long time ago, but it's not longer accurate so we had to remove it. We have no way of onboarding more people, short of meeting with them in person, which doesn't scale great.

The issue does not name a current file, test, or documentation entry point. Start by reviewing the repository's existing documentation and history for the removed tutorial, then define the onboarding scope and intended audience. Done means a current language tutorial is restored or added and can guide newcomers without requiring an in-person introduction.

Written by the indexing model from the issue text.