I've determined the first task Plover needs to fulfill.

Given a dictionary with four entries, {KA-T: cat, HR-OG: log, KA-T HR-OG: catalogue, HR-OG KA-T: Log Cat}, produce the following input/output results:

>>> KA-T
cat
>>> HR-OG
catalogue
>>> KA-T
catalogue cat
>>> HR-OG
catalogue catalogue
>>> HR-OG
catalogue catalogue log
>>> KA-T
catalogue catalogue Log Cat
>>> HR-OG
catalogue catalogue Log Cat log

(Log Cat is Log)