Пожалуйста, не пачкай новую рубашку соусом.

Пачкай is the imperative form of пачкать, meaning to dirty, stain, smear, or get something messy.

In this sentence, не пачкай means don’t get ... dirty.

This form is:

• singular
• informal
• used when speaking to one person you address with ты

If you were speaking politely or to more than one person, you would say:

• Пожалуйста, не пачкайте новую рубашку соусом.

This is a question about aspect.

• пачкать = imperfective
• испачкать / запачкать = perfective

With negative commands, Russian often uses the imperfective to mean something like:

• don’t do that
• don’t be doing that
• don’t get it dirty

So не пачкай sounds like a natural warning or instruction about the process/action.

A perfective version such as не испачкай is also possible, but it sounds more like:

• be careful not to stain it
• don’t end up getting it dirty

So the difference is roughly:

• не пачкай = don’t dirty it / don’t be getting it messy
• не испачкай = don’t accidentally stain it even once

Because it is the direct object of the verb пачкать.

The dictionary form is:

• новая рубашка = a new shirt

But after a transitive verb like пачкать, the direct object goes into the accusative case.

Since рубашка is:

• feminine
• singular

its accusative form is:

• рубашку

And the adjective must agree with it:

• новая → новую

So:

• новую рубашку = the/a new shirt, as the object of the action

Соусом is the instrumental case of соус.

Russian often uses the instrumental to show the substance, tool, or means involved in an action. With пачкать, you can ask:

• пачкать чем? = dirty something with what?

Answer:

• соусом = with sauce

So:

• пачкать рубашку соусом = to get the shirt dirty with sauce

This does not need the preposition с here.

Because с соусом usually means with sauce in the sense of accompanied by sauce, not by means of sauce.

Compare:

• рубашка с соусом — this would sound strange, like a shirt with sauce
• пачкать рубашку соусом — to dirty the shirt with sauce

So in this sentence, соусом without a preposition is the normal choice because it answers чем?

Пожалуйста means please here.

It softens the command, making it more polite or less harsh:

• Не пачкай новую рубашку соусом. = Don’t get the new shirt dirty with sauce.
• Пожалуйста, не пачкай новую рубашку соусом. = Please don’t get the new shirt dirty with sauce.

Its position is fairly flexible. For example, you could also say:

• Не пачкай, пожалуйста, новую рубашку соусом.

Both are natural.

No, Russian word order is fairly flexible.

The given order is neutral and natural:

• Пожалуйста, не пачкай новую рубашку соусом.

But other orders are possible if you want to emphasize something. For example:

• Не пачкай, пожалуйста, новую рубашку соусом.
• Новую рубашку соусом не пачкай.

The basic meaning stays the same, but the emphasis changes.

In the original sentence, the order is straightforward:

1. polite marker
2. negative command
3. object
4. what causes the mess

Because Russian has no articles.

So рубашка / рубашку can mean:

• a shirt
• the shirt

Which one is intended depends on context.

In this sentence, English might use the new shirt or a new shirt depending on the situation, but Russian simply says:

• новую рубашку

The listener understands from context which shirt is meant.

Usually рубашка means a shirt, especially something more like a button-up shirt or dress shirt.

It is not usually the normal word for a T-shirt. For that, Russian uses:

• футболка

So новая рубашка suggests a proper shirt rather than just any top.

Yes. Пачкать is a fairly broad verb. It can mean:

• to dirty
• to soil
• to stain
• to smear
• to mess up physically

In this sentence, because of соусом, the idea is specifically to get the shirt stained or smeared with sauce.

So the exact English wording can vary depending on context, but the Russian verb itself is very natural here.