Before you ask: Yes, this is real ancient greek and some of these words are still used in modern greek, so let's start:

Being ready:
Etimos (masculine) - ready
Etimi (feminine) - ready
Prostagma - command/order
Leje - collect/speak

Agreeing
Ne - yes
Voulume - I want to
Malista - very well
Orthos - right/correct
Kalos - good/well (literally "beautiful")
Esto - all right

Working
Metalefs - miner
Thireftis - hunter
Vouforvos - forage/berries
Drytomos - timber
Agrotis - farmer

In-Battle Commands
Proseche - watch out/be careful
Eisvoli - attack/invasion
Eis machin - to battle!
Pame - let's go
Porro - attack

This list may not be complete as I could have missed a word the people are saying. If you found one which is not in the list feel free to comment it below.