A pronoun is a word that takes the place of a noun. The use of Japanese personal pronouns is quite different from English. They are not used as often as their English counterparts, though there are a variety of pronouns in Japanese depending on the gender or the style of speech.
If the context is clear, the Japanese prefer not to use the personal pronouns. It is important to learn how to use them, but also important to understand how not to use them. Unlike English, there is no strict rule to have a grammatical subject in a sentence.
Here are some of the Japanese pronouns.
watakushi わたくし --- very formal
watashi わたし --- formal
boku (male) 僕, atashi (female) あたし --- informal
ore (male) 俺 --- very informal
otaku おたく --- very formal
anata あなた --- formal
kimi (male) 君 --- informal
omae (male) お前, anta あんた--- very informal
Among these pronouns, "watashi" and "anata" are the most common. However, as I mentioned above, they are often omitted in conversation. When addressing your superior, "anata" is not appropriate and should be avoided. Use the person's name instead.
"Anata" is also used by wives when they address their husbands. "Omae" is sometimes used by husbands when addressing their wives, though it sounds a little bit old-fashioned.
The pronouns for the third person are "kare (he)" or "kanojo (she)." Rather than using these words, it is preferred to use the person's name or describe them as "ano hito (that person)." It is not necessary to include gender.
I saw him (John) today.
Do you know her?
"Kare" or "kanojo" often means a boyfriend or a girlfriend.
Do you have a boyfriend?
My girlfriend is a nurse.
To make plurals, a suffix "~ tachi (～達)" is added like "watashi-tachi (we)" or "anata-tachi (you)". The suffix "~ tachi" can be added to not only pronouns but to some other nouns referring to people. For example, "kodomo-tachi (子供達)" means "children."
For the word "anata," the suffix "~ gata (～方)" is used sometimes to make it plural instead of using "~ tachi." "Anata-gata (あなた方)" is more formal than "anata-tachi." The suffix "~ ra (～ら)" is also used for "kare," such as "karera (they)."