Particles

In Japanese, most words have either particles or conjugation that follows them. These added parts give grammar and context to the words. Here are most of the particles:

は - (topic) Usually the focus of the sentence, though sometimes just the most important part.
ex. わたしはバカです。 I am an idiot.
わたしはえんぴつがある。 For me a pencil exists. (I have a pencil.)

が - Subject of the sentence, often replaced by は.
ex.　わたしがいる。 I exist.

を - Object of the sentence, replacable by は.
ex. これをよむ。 Read this. (Statement, not a request.)

と - Other subjects of the sentence.
ex. ともだちとあそぶ。 Play with friends.

も - Topic with same situation as previous statement.
ex. わたしはいる。あなたもいる。 I exist. You also exist.

に - Where and when the action takes place.
ex. いえにはしる。 Run (to/at) home.
ごじにたべる。 Eat at six o'clock.
ともだちにはなす。 Talk to friends.

へ - Where the action takes place towards.
ex. いえへいく。 Go (towards) home.

で - How or where an action takes place.
ex.くるまでいく。Go by car.
みせでかう。 Buy at shop.

から - When or where the action begins.
ex. いえからはしる。 Run from home.

まで - When or where the action stops.
ex. ここまではしる。 Run until here.