Translation guide
Expresses that two or more actions, events, or states occur at the same time. Japanese uses various patterns depending on whether the subjects are the same, the actions are ongoing, or the timing is precise.
I study while listening to music.
Adverb meaning 'at the same time' or 'simultaneously'. Can be used with different subjects.
The two started speaking simultaneously.
Pattern meaning 'at the same time as ~'. Used with nouns or verbs in dictionary form.
The meeting started simultaneously as he entered.
Means 'together with' or 'as'. Indicates that one change or action happens along with another. Slightly formal.
As you age, your physical strength declines simultaneously.
To describe doing one action in the middle of another ongoing action, often with the same subject.
Means 'while ~ is happening'. The second action occurs during the first. The subject can be the same or different.
I read a book while the child was sleeping.
Similar to ながら but more formal and often used in writing. Attaches to verb stem.
He thought while walking.
To emphasize that two events occur at precisely the same instant.
To describe multiple people doing something at the same time.
Adverb meaning 'all at once' or 'in unison'. Used when a group acts simultaneously.
The students stood up simultaneously.
ながら is used when the same person does two actions at once, and the first action is the background activity. 間に is used when an action takes place during a time period, and the subjects can be different.
I eat while watching TV. (same person)
While I was cooking, he cleaned. (different people)
While 同時に is a direct translation, it can sound stiff in casual conversation. Use ながら or 〜ている間に for natural speech.
As soon as he arrived home, it started raining.