+1, I learned English by playing Leisure Suit Larry I-III [1]. Text adventures were really useful in this regard because you had to type in more or less correct sentences. Also, at the core they were built around dialogues, that is, spoken (=not very formal) language and vocabulary.

Al Lowe, lead developer of the Larry series, probably also had some influence on my sense of humor (to this day I prefer grammar-level jokes to kicks-in-the-butt). These games were a great, intellectually twisted, multi-layered introduction to the world of adult people as well. :) Thank you, teacher!

1: https://en.wikipedia.org/wiki/Leisure_Suit_Larry_in_the_Land...