Concurrence with ながら, あいだ, うちに, and つつ

This lesson focuses on how to state that something happens while something else is going on.

ながら states that two actions are concurrently true as they happen at the same time. The subject of the two actions must be the same. Like “I watch TV while eating chips” is okay, but “I watch TV while my brother plays video games” is not. ながら attaches to the masu stem of the verb.

ながら is in the form of AながらB, where the action described by B is the “primary” action and the action described by A is a “secondary” action that is done at the same time. In English this nuance does not easily show up, so let’s look at two examples instead:

画面を見ながら勉強しよう
Let’s study while looking at the screen.

そこで勉強しながら、爺ちゃんの帰りを待つ
I waited for grandpa to come home while studying there

In the first first example, the main action is to study and that is what the speaker wants to do, while in the second example the speaker is focused on the action of waiting, and while doing so they study.

つつ is another auxiliary that can be used more or less the same as ながら, except it sounds more formal and is almost only relegated to literary sentences.

彼女はそう言いつつ、苦笑いを浮かべる。
While she was saying that, she showed a bitter smile.

つつある is a special usage of つつ that implies an action is happening continuously, like a more formal ている.

時代は変わりつつあります。  
The ages are continuously changing.

However, unlike ている it cannot be used for verbs that describe states to mean "to be in a state of":

男はもう死につつある。
The man was already dying.

男はもう、死んでいる。
The man was already dead.

間/あいだ(に) and うちに are two other ways to state that something happens while something else is happening, however the usage is more general and they have a broader scope than ながら and つつ.

間/あいだ says that two events happen the same span of time in its entirety. This places constraints on what sorts of statements it accepts. 間 itself acts like a noun.

私がお風呂に入っている間、何をしているのですか？
What were you doing the entire time I was in the bath?

A間にB says that B starts and ends within the time A takes place.

俺が意識を失っている間に何があったのだろうか？
I wonder if something happened while I was out unconscious? 

うちに says that an event happens while the statement before うちに remains true.

そんな事を考えているうちに、完全に日が沈んでしまった。
While I was thinking about that stuff, the sun set completely. 

It often has a nuance that the event marked by うちに is limited in time and will eventually finish.

蜘蛛がいないうちに救出するか
Are you going to rescue them while the spiders are away?

This is often used to give recommendations or suggestions like “before X happens, we should do Y”

冷めないうちに食べましょう。
Let’s eat before it gets cold. (lit. let’s eat while it is not cold)