Hi...is it possible to for a map script to display messages to specific players, or do they have to be global?
For example, only to one player or only to one team?
I am not talking about chat 
Also, would it be possible to change colour of a single unit or can you only change army colour, of an entire army? I suppose the answer to both of these is a firm NO, specially to the second one 
In the in game chat window, you can select to which player you want to send a message. Even in the lobby you can do that with /w playername I think.
@zokora no, i meant via map script, not chat messages. Instructions on nhow to play a map, or a welcome message...that sort of thing
I think that is possible too, I'm not entirely sure. You'd need to check the UserSync.lua in /lua and /schooks/lua. Also - best to ask in #modding-general in my opinion
A work of art is never finished, merely abandoned
@dddx
Yes, it is possible to display messages to specific players. For example, the map Tower Defense Survival does this by selectively displaying messages via PrintText() if the focus army's index (via GetFocusArmy()) matches the army index(es) that you desire the message to be displayed for. You can look at Tower Defense Survival's map script and or ask in #modding-general on discord if you need more help with that (you can opt-in to the modder role on the FAF discord to see the #modding-general channel).
pfp credit to gieb