I dunno - I just asked my agent what he'd make:

  You start fluent in your grandmother's language and, over 25 years of play,
  lose it word by word.
  - New: language games are about learning. This one runs that process backward,
    so forgetting is the main mechanic. You never fail a conversation. You just
    have fewer words to say it with, and Nana switches to slow English to meet
    you.
  - Closest games: Venba, where the loss is scripted, and Chants of Sennaar,
    where you decode languages instead of losing one.
  - Moment of play: you're 31 in an airport, on the phone with Nana, with seven
    word tiles left. She says "Okay. Good. You eat?" and you watch a tile
    dissolve.