〜たい

1. Origins, structure, and basic meaning

• Structure: Remove ます from a verb's polite form and add たい.
  • 行きます → 行きたい, 訪れます → 訪れたい
• Basic usage: It expresses the speaker's desire to perform an action.

2. Common pitfalls and similar expressions

• Inflection after たい
  • It inflects like an i-adjective, as in 行きたくない and 行きたかった. Add です after these forms for polite speech.
• Particles for objects and destinations
  • Both 水を飲みたい and 水が飲みたい are used. This does not establish the same substitution rule for the destination particle へ in 海へ行きたい.
• Asking about another person's wishes
  • A question such as 何を食べたいですか can ask about the listener's wishes. Another person's desire can be reported with a form such as 行きたいと言っています, which makes their statement the basis of the report.