Working through conversations, and I thought I'd describe how it works.
Conversations can only be between two people. Starting a conversation with a second person will end it with the first.
Conversations are started with the command "(say) hello (to [character])." Only the "hello" is necessary; the engine will attempt to disambiguate what you mean in most cases (Hello will default to a random person; other examples, such as "take log" when you can see a burnt log and a smelly log, will ask you which one you meant) but specifying the exact character is generally a good idea.
I previously stated that talking would be built off of a node system. For the purposes of simplicity, I've decided to scrap that. Pressure is not a heavily social game, and the benefits of a node system would largely go unused. Instead, I am using a traditional ask/response style. Conversational commands include ask, tell, show, and give. Typing "Show Cook the frozen fish" will check if there is a default response for the cook for showing the frozen fish, then check for a default showing response, and finally a default response. The consequence of this is that there will be a lot of "default" responses as I build up the conversation library.
Added on to this is a knowledge and subjects system. Inform likes to treat everything as a physical object. This works fine, until you want to discuss love with the mechanic. So, subjects allow for out-of-world ideas that can be discussed. The knowledge system compounds this. You can only discuss things that you know about. So, if you (the character) have no inkling that there's a conspiracy going on, or that a plant is murdering crew members in their sleep, you (the character) can't immediately start the game and ask about them.
I've only really completed one character's entire conversation library, so it'll probably take a while to finish all of the existing characters'. I'll keep you posted though.