When someone thanks you by saying "ARIGATOO" or more politely "ARIGATOO GOZAIMASU," you can reply by saying "DOO ITASHIMASHITE."
"Doozo." = Please.
"Arigatoo." = Thank you.
"Doo itashimashite." = You're welcome.
Note: In the system of romanization used in this section, "ee" is not pronounced like feet. Instead, it means that the vowel sound "e" as in pet is prolonged. In the same manner, "oo" is pronounced not like shoot but as the "o" vowel, similar to pork, pronounced twice as long.