Translations:

Masaka= so.../ you mean...
(you say it when you realize something but you stopped in the middle)

Ara Ara= oh my.../ seriously...
( like a small joke, girls say this to tease people)

ii deshou ka= are you all right../ is it okay..
( this phrase might mean "Is it alright?" or "Are you okay")

San= a title used as a sign of respect (Mr. or Mrs)

Sensei= a title used as a sign of respect (used for teachers and doctors)