No deixis el paper al bany; posa el paper sobre la taula.

Because this is a negative command addressed to tu.

In Catalan, negative commands for tu use the present subjunctive, not the ordinary present tense:

• deixes = you leave / you put down (statement)
• no deixis = don’t leave

So:

• No deixes el paper al bany = You don’t leave the paper in the bathroom
• No deixis el paper al bany = Don’t leave the paper in the bathroom

This is one of the most important command patterns to learn in Catalan.

Because positive commands for tu usually use the imperative form, while negative commands use the subjunctive.

So:

• posa = put
• no posis = don’t put

That gives you this contrast:

• Posa el paper sobre la taula. = Put the paper on the table.
• No posis el paper sobre la taula. = Don’t put the paper on the table.

In your sentence:

• No deixis... = negative command
• posa... = positive command

Here deixar means to leave or to put something somewhere and leave it there.

So No deixis el paper al bany means:

• Don’t leave the paper in the bathroom

Depending on context, deixar can also mean other things, such as:

• to let / allow
• to leave behind
• to stop / quit in some expressions

But in this sentence, the meaning is clearly leave.

Al is a contraction of a + el.

• a = to / at / in
• el = the
• a + el = al

So:

• al bany = in the bathroom / to the bathroom / at the bathroom, depending on context

In this sentence, the natural meaning is in the bathroom.

Examples:

• Vaig al bany. = I’m going to the bathroom.
• És al bany. = He/She is in the bathroom.

Catalan often uses a where English uses in, at, or to.

Catalan uses the definite article much more often than English does.

So el paper is completely normal, even where English might say simply paper or the paper, depending on context.

In this sentence, el paper probably refers to a specific piece of paper or a known item in the situation.

This frequent use of articles is very common in Catalan:

• M’agrada el cafè. = I like coffee.
• Tinc el cotxe fora. = I have the car outside.

So don’t be surprised if Catalan sounds more article-heavy than English.

They express location in different ways:

• al bany = in/at the bathroom
• sobre la taula = on the table / on top of the table

The key word in the second phrase is sobre, which means on, on top of, or over, depending on context.

So:

• posa el paper sobre la taula = put the paper on the table

This is more specific than just indicating a general place. It tells you the paper should be physically on top of the table.

Not usually if you mean on top of the table.

• sobre la taula specifically means on the table
• a la taula often means at the table

So these are different:

• El llibre és sobre la taula. = The book is on the table.
• Som a la taula. = We are at the table.

If you want the physical location on top of the surface, sobre is the safer choice.

Yes, Catalan could use a pronoun, but repeating the noun is also perfectly natural.

Your sentence says:

• No deixis el paper al bany; posa el paper sobre la taula.

This is very clear and straightforward.

A more compact version could be:

• No deixis el paper al bany; posa’l sobre la taula.

Here ’l means it and attaches to posa:

• posa’l = put it

Both versions are correct. Repeating el paper can sound clearer, especially for learners or when emphasis is useful.

No. They just happen to look the same.

In this sentence, deixis is a verb form from deixar.

In linguistics, English deixis is a technical noun meaning something like reference that depends on context, as in this, that, here, now, etc.

So although the spelling matches, the meaning is completely unrelated here.

It is addressed to tu, the informal singular you.

You can tell from the verb forms:

• deixis
• posa

These are forms used for commands to one person you would address as tu.

If you were speaking formally to one person (vostè), or to more than one person (vosaltres / vostès), the verb forms would change.

For example:

• No deixi el paper al bany; posi el paper sobre la taula. = formal singular
• No deixeu el paper al bany; poseu el paper sobre la taula. = informal plural

Literally, paper just means paper.

By itself, it does not automatically mean toilet paper. If someone specifically means toilet paper, Catalan often says:

• paper higiènic

So:

• el paper = the paper
• el paper higiènic = the toilet paper

That said, the surrounding context might make one interpretation more likely. Since the sentence contrasts the bathroom and the table, many learners may wonder about this, but grammatically the word here is simply paper.

The semicolon links two closely related commands:

• No deixis el paper al bany
• posa el paper sobre la taula

It shows that the two ideas belong together:

• don’t leave it there
• put it here instead

A comma is sometimes possible in informal writing, and a full stop would also work, but the semicolon neatly connects the two instructions as parts of one thought.