you say aloha
Mahalo Nu'i Loa
Aloha. Answer: Mahalo pilialoha.
Aloha: Answer: You say Mahalo. Pau 'ana (ma-ha-low. Pow ah-nah) It is also ok to just say Pau after mahalo (thank you), but adding the 'ana is better.
Thank you in Japonese is arigato gozimus, now it is spelt the way it sounds, not the real spelling I don't think