がる・
Japanese doesn't normally state another person's feelings or wants as a plain fact. がる turns the feeling into something they do: 怖い, scared, becomes 怖がる, and 行きたい becomes 行きたがる.
wanting to do
My little sister wants to go to Japan.
wanting a thing
My little brother wants a new game.
A feeling
怖い → 怖がる ／ ほしい → ほしがる ／ 嫌 → 嫌がる
An い-adjective loses its い; a な-adjective takes がる as it is. It goes on words for feelings and sensations, not on adjectives like 大きい or きれい.
Wanting to do
行きたい → 行きたがる
The い of たい comes off the same way.
Its own forms
がる・がります・がって・がらない・がった
It is a godan verb (う-verb).
Your feelings, and theirs
寒い, 痛い, ほしい and 行きたい are for the person who feels them. About someone else you say what they show, how they look, or what they told you.
Not said: 妹は
(My little sister is cold.)
My little sister is cold.
She shows it: she is shivering, or complaining.
My little sister says she is cold.
What she told you.
がる makes a verb, so what took が now takes を.
The ones you will hear
怖がるbe scared of
When the children see a large dog, they hide behind their parents in fear.
嫌がるdislike, resist
The cat hates having water splashed on it, and flattens its ears.
恥ずかしがるbe shy
When a stranger speaks to my daughter, she hides behind me out of shyness.
残念がるbe disappointed
When she heard the result, she lowered her eyes in disappointment.
好き and 嫌い don't need it
They describe the person, so they are fine about anyone, and so is 上手: 弟は犬が好きです.
Now, or in general
がっている is how someone is now or these days. Plain がる is what they are generally like.
now
The dog is scratching at the door with its front paw and wants to go outside.
every morning
Every morning, my daughter reaches for the red shoes and wants to wear them.
たがる and たがらない
たがる is たい seen from outside: someone shows that they want to. たがらない says they are unwilling.
Yuto keeps yawning and wants to go to bed already.
Even after being tucked in, my son kept getting up and did not want to sleep.
My father doesn't want to go to the hospital.
He doesn't like to talk about the past.
Who it isn't said about
About yourself, the plain word is enough: 寒いです. がる watches someone from outside, as you would a child or a pet, so it can sound rude about a teacher, a boss or a customer. You say what they told you.
Sounds odd: 部長も
The manager wants to go too.
部長も行きたいそうです, "I hear the manager wants to go too".
To someone's face you ask: 寒いですか. What people do say to them is がらないで.
Please don't be scared.
Don't be shy; please try speaking.
寒がり: the kind of person
がり or がり屋 makes a noun for a person who feels something easily: 暑がり, 怖がり, 寂しがり屋. These you can say about yourself.
I feel the cold easily, so I don't do well in winter.
My little sister is shy.
Close neighbours
てほしいN4
What you want someone else to do. たがる is what they want to do themselves.
I want my mother to get some rest.
Check yourself
1Which sentence sounds natural?
Choose an answer to see why.
2"My little brother wants to see that film."
弟は
Choose an answer to see why.
3Which particle?
子どもが
Choose an answer to see why.
More detail
かわいがる and 強がる
Two words with meanings of their own: かわいがる, to be fond of someone and look after them, and 強がる, to act tougher than you feel.
My grandmother dotes on my little brother.
More sentences
Our dog is so afraid of loud noises that it hides under the desk when it thunders.
The players who had lost the match were disappointed, their shoulders slumped.
The baby is reaching for the spoon and wants to feed itself.
At the front door, the dog had its leash in its mouth and wanted to go outside.
When the child sees a syringe, they cry and hide their arm; they don't want the injection.