Pardon, je ne comprends pas.

Here, pardon means something like sorry?, excuse me?, or pardon me? It is often used to politely signal that you did not catch or understand what someone said.

In this sentence, it softens what follows:

• Pardon, je ne comprends pas. = Sorry, I don’t understand.

It is polite and very common.

Not exactly, but it overlaps a lot.

Pardon can be used:

• to apologize lightly: pardon
• to ask someone to repeat: pardon ?
• to politely interrupt: pardon

So in this sentence, it is closer to sorry or excuse me than to a strong apology.

Because standard French usually makes a sentence negative with two parts:

• ne
• pas

So:

• je comprends = I understand
• je ne comprends pas = I do not understand

This is the normal pattern for negation in standard French.

In careful or formal French, yes:

• Je ne comprends pas.

But in everyday spoken French, many speakers drop ne:

• Je comprends pas.

That is very common in conversation, but learners should still know the full standard form, especially for writing and more formal situations.

Comprends is the present tense, first person singular, of the verb comprendre.

So:

• je comprends = I understand
• je ne comprends pas = I do not understand / I’m not understanding

In natural English, this usually becomes I don’t understand.

Because that is the correct je form of comprendre in the present tense.

Present tense forms:

• je comprends
• tu comprends
• il / elle / on comprend
• nous comprenons
• vous comprenez
• ils / elles comprennent

The s is part of the spelling of the je form, even though it is not strongly pronounced on its own.

A simple pronunciation guide is:

par-don, zhuh nuh kom-pran pah

A few notes:

• je sounds like zhuh
• ne is often a very light nuh, or may almost disappear in fast speech
• comprends has a nasal vowel near the end: kom-pran
• pas sounds like pah, not like English pass

In everyday speech, you may hear something closer to:

• Pardon, je comprends pas.

You can, but it more specifically means I do not understand, not I did not hear.

So if the problem is meaning, this sentence is perfect:

• Pardon, je ne comprends pas.

If the problem is that you simply did not hear the words, French often uses:

• Pardon ?
• Je n’ai pas entendu. = I didn’t hear.
• Pouvez-vous répéter ? = Can you repeat?

This is a useful distinction:

• not hearing = sound problem
• not understanding = meaning problem

Yes, it is polite and natural.

Adding pardon makes the sentence softer and more courteous than just saying:

• Je ne comprends pas.

It is a good phrase to use with strangers, teachers, staff, or anyone you want to be polite with.

Yes.

• Je ne comprends pas. = I don’t understand.

That is completely correct. Adding pardon just makes it more polite or more conversational in the moment:

• Pardon, je ne comprends pas.

So both are fine, but the version with pardon sounds gentler.

Yes.

• Je ne comprends pas = I don’t understand / I’m not understanding
• Je n’ai pas compris = I didn’t understand

The first is present tense and describes your current lack of understanding. The second is past tense and often means you did not understand what was just said.

For example:

• Someone explains something, and you are still confused: Je ne comprends pas.
• Someone said something quickly, and you missed it: Je n’ai pas compris.

Both are common.

Yes. Depending on the situation, you might also hear:

• Excusez-moi, je ne comprends pas. = more formal / very polite
• Désolé, je ne comprends pas. = Sorry, I don’t understand
• Pardon ? = Sorry? / Pardon?

But pardon is short, polite, and very useful, so it is a great phrase to learn early.

Normally, no. In standard French, the subject pronoun is usually required.

So you say:

• Je ne comprends pas.

not just:

• Ne comprends pas.

French verbs usually need the subject pronoun to make the sentence sound complete and natural.