just a small suggestion like press "t" or "y" to bring up a typing bar.
edit : press F2 then 4 to open chat, press F1 to close.
This guide describes new hotkeys for the Steam version.
Also, at the end there is a link to another guide where a player writes about how to change hotkeys according to your own taste. It may be useful for someone, though it changes these hotkeys for the whole system at once.