Lesson 32: Cause and reason (vì, tại, do)

Explaining why something happened involves linking a cause to an effect.

Neutral Causality with "vì"

Vì is the standard word for "because." It is almost always paired with nên (so) to complete the thought.

Vì trời mưa nên tôi ở nhà.
"Because it rains, (so) I stay home."

Blame with "tại"

Use tại when the reason is a mistake or something negative ("because of").

Tại anh nên chúng ta muộn.
"Because of you, (so) we are late."

Formal Origin with "do"

Do is often used in formal contexts or for technical/logical reasons ("due to").

Tai nạn do bất cẩn.
"Accident due to carelessness."

The "Cause... Result" Frame

The Vì ... nên ... structure acts as a frame for your sentence. Even if English drops the "so," Vietnamese usually keeps nên.

Vì mệt nênđi ngủ sớm.
"Because (I'm) tired, (so) (I) go to sleep early."

Examples

Tại tắc đường nên đến trễ.
"Because of traffic jam, (so) arrived late."

Vì thích tiếng Việt nên học mỗi ngày.
"Because (I) like Vietnamese, (so) (I) study every day."

Note on nuance

Be careful with tại—it implies fault. If you say Tại bạn, you are accusing someone! For neutral explanations, vì is always safe.