Tôi sẽ gọi điện cho mẹ sau giờ làm.

Sẽ is a future marker. It shows that the action will happen later, similar to will in English.

• Tôi gọi điện cho mẹ = I call / I am calling my mother
• Tôi sẽ gọi điện cho mẹ = I will call my mother

Vietnamese does not always need a future marker if the time is already clear from context, but sẽ makes the future meaning explicit.

Gọi điện specifically means to phone / to make a phone call.

• gọi by itself can mean to call, but it can also mean to call out, to summon, or to name
• gọi điện makes it clear that this is a telephone call

So in this sentence, gọi điện is the natural way to say call someone on the phone.

In gọi điện cho mẹ, cho marks the person who receives the action, so it works a bit like to in English:

• gọi điện cho mẹ = call mother / call my mother
• more literally: make a phone call to mother

In many Vietnamese sentences, cho can also mean for or to give, but here it introduces the recipient of the phone call.

Vietnamese often leaves out possessives like my when they are obvious from context.

So:

• mẹ = mother / mom
• mẹ tôi = my mother

In a sentence starting with Tôi (I), it is already very natural to understand mẹ as my mother. Saying mẹ tôi is still possible, but it can sound more explicit or slightly heavier than needed in casual speech.

Vietnamese usually follows a straightforward order:

subject + time/future marker + verb + object/recipient + time phrase

So here:

• Tôi = I
• sẽ = will
• gọi điện = call
• cho mẹ = to mother / my mother
• sau giờ làm = after work

This gives:

Tôi sẽ gọi điện cho mẹ sau giờ làm.

The recipient comes after the verb phrase, which is normal in Vietnamese.

Sau giờ làm means after work or more literally after work hours.

Breakdown:

• sau = after
• giờ = hour / time
• làm = work

Together, giờ làm refers to working time or work hours. So sau giờ làm means after the work period is over.

Yes, but it means something slightly different in tone and structure.

• sau giờ làm = after work / after working hours
• sau khi làm việc = after working / after finishing work

Sau giờ làm is more natural for everyday conversation when talking about calling someone after the workday.
Sau khi làm việc sounds more formal or more literal.

Not always.

• làm can mean do, make, or work, depending on context
• làm việc specifically means to work

In giờ làm, the shorter form làm is natural because it refers to work time. Vietnamese often uses shorter expressions when the meaning is clear.

Yes. Vietnamese time expressions are fairly flexible.

You can say:

• Tôi sẽ gọi điện cho mẹ sau giờ làm.
• Sau giờ làm, tôi sẽ gọi điện cho mẹ.

Both are correct. Putting sau giờ làm first gives it a bit more emphasis, like After work, I’ll call my mother.

Grammatically, tôi is a standard and safe way to say I, but Vietnamese pronouns depend heavily on relationship, age, and social context.

For example, in real life a speaker might say:

• con when speaking to their mother
• em, anh, chị, etc. in other relationships

So a more natural family version might be:

• Con sẽ gọi điện cho mẹ sau giờ làm.

That would sound very natural if a child is speaking to or about their mother. But tôi is still perfectly correct as a neutral learning example.

Usually, with gọi điện, cho is the most natural choice:

• gọi điện cho mẹ = call mother

Omitting cho would sound unnatural in standard Vietnamese for this meaning. So learners should treat gọi điện cho + person as a useful pattern.

It is neutral and natural. The level of formality mainly depends on the pronoun choice.

• Tôi sẽ gọi điện cho mẹ sau giờ làm. = neutral, standard
• Con sẽ gọi điện cho mẹ sau giờ làm. = more natural in a family context
• Tớ sẽ gọi điện cho mẹ sau giờ làm. = more casual, depending on who is speaking

So the sentence itself is fine, but in real conversation native speakers often adjust the pronouns to fit the relationship.