Politeness
Japanese has two different ways to form polite expressions. One is to show respect to the addressee. This is called an "honorific expression," and the other is to lower yourself (the speaker) or someone in your group. This is called a "humble expression."
Generally speaking, an honorific expression is used when the addressee is older or higher in social status. The longer the expression is, the more polite it tends to be.
There are two ways to make honorific verb forms in Japanese. One is to add the prefix "o-" in front of the verb stem and add ni naru (-ni narimasu). The other is to make the verb passive. Also, there are certain irregular honorific verbs such as "Goran-ni-naru" (honorific form of "miru" to see), "Irassharu" (honorific form of "iru"-to exist, "kuru" to come and "iku"-to go) and "Nasaru" (honorific form of "suru"-to do).
Honorific adjectives and nouns are formed by adding the prefix"o-". Some nouns take the prefix "go-" instead of "o-." "O-" is used for the traditional Japanese word or Japanized noun, while "go-" is used for the Japanese word whose origin is from Chinese.
Humble verbs are formed by adding the prefix "o-" and also "-suru" (-shimasu) to the verb stems. There are certain irregular humble verbs such as "Haiken-suru" (humble form of "miru" to watch), "Mairu" (humble form of "kuru" to come), "Itasu" (humble form of "suru" to do).
In addition to the honorific forms and humble forms, there is another "polite" form in Japanese. This uses "-de gozaimasu," which is the polite form of the copula "da." This is formed by adding "-de gozaimasu" after nouns, Na-adjectives or nominalized verbs.
In order to master the polite speech, it is necessary to understand
the social and cultural aspect of Japanese. You need to know when and how
to elevate somebody. For example, when you talk to somebody who seems older,
you use honorific forms. However, when you are talking about the older
person who is your in-group member (usually your family member or people
at your company, including your bosses), you use the humble form to indirectly
elevate the addressee. This is why Japanese people try to obtain personal
information (such as job, marital status, age, etc.) as soon as they meet
someone new in order to know which form they should use.