this doesnt work, but it might be on the right lines if you can work it out!
ask them 'is the sky blue'?
ask them again
the random one will answer differently, so you know what he is. eliminate him.
with the other two (truth and lies), ask 'if you were the other god, would you say [the god on the right hand side] is the lying god"?
say the god on the right is the lying one.
truth god will say 'no'
lying god will say 'no'
so we know the god on the right IS the lying god.
you could then identify what ta and ka mean from their answers to the first question, but ONLY if they answer in english for the third question, so it doesnt work!!
it might be something simpler, but i dont know. hope i guided you.