In Agatha Christie’s works, which languages does Hercule Poirot speak, in addition to French and English?

A devoted Agatha Christie fan, I spent years tracking down "Black Coffee". The comments on the back cover were glowing. But it was dreadful. The person - and I can't remember who it was - who completed the novel from the play/story line failed miserably. Dame Agatha Christie could make one 'see' the people, the rooms, buildings, the weather and atmosphere of which she wrote! I could have done a better job myself.