As we explored in our lesson about
がる, this verb can be used with adjectives, to express the way in which people are acting. However, it can also be partnered with the
auxiliary verb たい, to form
たがる. This grammar construction is used when expressing that someone is acting like they 'want' to do something.
To use this structure, attach
たい to the ます stem form of any verb, then replace the い in
たい with
がる.
ジョンはなんでいつも悪口（わるぐち）を言（い）いたがるんだろう。
I wonder why John always wants to talk badly about people.
皆（みんな）は彼（かれ）が作（つく）ったケーキを食（た）べたがる。
Everyone always wants to eat the cakes that he makes.
たがる is in contrast to
てほしい which means 'to want someone to do (A)'. These differences will need to be practiced, and memorized.
This is also in contrast to the
い-Adjective 欲（ほ）しい 'to want (A)'. To describe that someone seems like they want something (rather than that they want to 'do' something),
がる will be paired with this adjective.