Exsurgent: In the comments section, she also says:
"Heaven's Vault involves a lot more active translation of the alien language, and using your knowledge to expand your understanding of words and phrases to tackle more complex sentences. Grotto's scope is much narrower. You only ever have to think about the meaning of these 24 symbols, but the way they change isn't nearly as organic as HV. It's much more prescribed by the circumstances of the story rather than your own understanding of it.
In fact, Heaven's Vault is probably exactly what people should play if they like the language aspect of Grotto, but want a proper branching narrative game with meaningful choice and consequences like I mention at the end!"
No idea if this reflects the experiences of the people around here who've already played the game, but maybe this will help some other people who might be interested in the game.
Boy Katherine, jerk off Heaven's Vault a little more, why don't you? I can tell you sight unseen that the two games are going for very different things with their stories, their gameplay, and their exploration of "language".
"You only ever have to think about the meaning of these 24 symbols, but the way they change isn't nearly as organic as HV. It's much more prescribed by the circumstances of the story rather than your own understanding of it." Yes, indeed, I believe that's the point. Grotto is less of a game about understanding the constellations and more a game of understanding people.
