What it means
たい expresses a desire to perform an action, such as wanting to buy, eat, or go somewhere. It attaches to the masu stem of a verb. It is commonly used for the speaker's own wishes; when describing another person's apparent desire, たがる is usually more natural. たい behaves like an i-adjective, so it can take polite endings such as です.
Usage note
たい attaches to the masu stem, not directly to the dictionary form. A destination is normally marked with に or へ; を or が can mark the desired object in relevant constructions, but they do not generally mark a desired destination.
How to use it
私は新しい自転車を買いたいです。
I want to buy a new bicycle.
私は新しい自転車を買いたい。
I want to buy a new bicycle.
Example sentences
週末に新しい靴を買いたいです。
I want to buy new shoes this weekend.
夏休みに海で泳ぎたいです。
I want to swim in the sea during summer vacation.
仕事のあとで図書館へ行きたいです。
I want to go to the library after work.
今夜、家でカレーを作りたいです。
I want to make curry at home tonight.