The context menu for clothing items includes "wear", and the context menu for nearby avatars on the Chat page includes all the actions available with the buttons. But the menu for Notecards in Inventory does not include "open", and the menu for Landmarks does not include teleport..
The visual behavior for LMs is that a Teleport button appears, but that is not reflected in the ContextMenu, which is what the speech interface looks at.
The visual behavior for selecting a Notecard with the mouse includes fetching the text and putting it over to the right. But stepping onto a notecard with the arrow keys does not do this (and this is the way a blind person would get there). Even if it did fetch the card text, that would slow things down considerably, and even more so were the Speech interface to start reading it without being asked.
If the context menu on Inventory items included all the obvious things to do with an item (wear, take off, open, teleport, etc), even when it duplicates other ways of getting to them, that would provide a consistent way to discover the actions.