Yup, around 10. Set in Liliput, because I’d just read Gulliver’s Travels, and accompanied by some map drawing. Inspired by the Latin textbooks I was poring over, and it had a hell of a lot of declension tables. And diacritics. El Glheþ Talossan-level diacritics. Coz they’re k00l.
It wasn’t full, because I don’t think I understood enough about language back then; vocabulary was never a problem though—there’s always more Latin where that came from. Never taught it to anyone. Don’t remember a thing about it.