ながらwhile doing
One person does two things at once. What they are mainly doing comes last, and what goes on alongside it takes ながら.
I do my homework while listening to music.
Let's check today's schedule over coffee.
How to form it
Verb ます-stem + ながら
The ます-stem is the ます-form without ます: 聞きます → 聞きながら, 食べます → 食べながら, します → しながら. The verb at the end of the sentence shows the tense and the politeness.
Two things at once
I ate dinner while watching television.
He came into the room laughing.
Please do not look at your phone while walking.
The main thing comes last
The verb at the end is the main thing. The ながら part is what goes on alongside it. In English either half can come first; in Japanese the order tells you which is which.
Let's talk while we eat.
The talk is the point.
Let's eat while we talk.
The meal is the point.
One person, not two
English "while" can join what two different people are doing. ながら can't: both actions belong to the same person.
My mother was talking with my younger sister while cooking.
My mother does both.
Not said: 母が
(While my mother cooked, I did my homework.)
Two people. Say 母が料理をしている間に、私は宿題をしました.
Over months, not only minutes
The two things don't have to happen in the same minute. ながら also joins two things someone keeps up over the same period.
My older sister is studying in college while working.
Close neighbours
ている間にN4
"While" when two different people or things are involved.
I cleaned while the children were asleep.
てN4
How you are while you do something: sitting, standing, holding or wearing something. That isn't a second activity, so it is usually the て-form, not ながら.
Let's sit down and talk.
ながら（も）N2
The same word with another meaning: "although". It usually follows a state, such as knowing, and not something you are busy doing. 残念ながら ("unfortunately") is this one.
He knew, and yet he said nothing.
Check yourself
1Which sentence is natural?
Choose an answer to see why.
2Which one fits?
音楽を
Choose an answer to see why.
3What is she mainly doing?
姉は
Choose an answer to see why.
More detail
ながらスマホ
On posters and in the news, ながら also stands in front of a noun: ながらスマホ is using your phone while doing something else, and ながら運転 is driving while doing something else, such as using a phone.
More sentences
I walked to the station while eating some bread.
I practice pronunciation while listening to the audio.
Let's talk as we walk.