Извини, я забыл.

In Russian, past-tense verbs agree with the speaker’s gender, not with the person in the same way English does.

• я забыл = I forgot if the speaker is male
• я забыла = I forgot if the speaker is female

So забыл is the masculine past-tense form.

Извини is informal singular. You use it with:

• one friend
• someone your age in a casual situation
• a child
• someone you address with ты

The formal or plural version is Извините. You use Извините with:

• strangers
• older people
• people in professional settings
• more than one person

So:

• Извини, я забыл. = informal
• Извините, я забыл / забыла. = formal

Russian often leaves out the object if it is already understood from context.

In English, you often say I forgot it or I forgot about it. In Russian, if everyone already knows what is being talked about, you can simply say:

• Я забыл.

If you want to mention the thing explicitly, you can add it:

• Я забыл ключи. = I forgot the keys.
• Я забыл об этом. = I forgot about that.

So the short sentence sounds very natural.

Because Извини is being used as a separate introductory apology, like:

• Sorry, I forgot.

The speaker first says Извини and then gives the explanation я забыл. In writing, Russian separates those parts with a comma.

Both can mean sorry or forgive me, but they are not always identical in tone.

• Извини is very common for everyday situations: small mistakes, interruptions, forgetting something.
• Прости can sound more emotional, deeper, or more personal, though in many contexts it is also just sorry.

In this sentence, Извини, я забыл sounds very natural for an ordinary apology.

Забыл comes from забыть, which is a perfective verb.

Perfective verbs usually present an action as a complete event or result. Here the speaker means a completed fact:

• I forgot.

That is why забыл works well.

The imperfective partner is забывать. Its past form would be забывал / забывала, but that would usually suggest repeated action, process, or a different nuance, not the simple completed apology used here.

The stress is:

• извини
• я
• забыл

A rough pronunciation guide:

• Извини ≈ eez-vee-NEE
• я ≈ ya
• забыл ≈ zuh-BEEL

The stressed final syllables in извини and забыл are important.

Yes. Извини can be used both for:

• sorry
• excuse me

depending on context.

For example:

• Извини, я забыл. = Sorry, I forgot.
• Извини, где метро? = Excuse me, where is the metro?

So the exact English translation depends on the situation.

Yes, you can, but меня is often omitted.

• Извини. = Sorry.
• Извини меня. = Forgive me / Sorry with a bit more emphasis

In everyday speech, Russian often prefers the shorter version unless there is a reason to stress it. So Извини, я забыл is the most natural simple phrasing here.

Yes, Russian can sometimes omit subject pronouns, especially when the meaning is clear from context.

So you may hear:

• Извини, забыл.

This still means Sorry, I forgot, and it is very natural in conversation.

However, я can be included for clarity or emphasis:

• Извини, я забыл.

Both are correct. The version with я is a little more explicit.