A inquilina com quem falei quer pintar a sala antes de levar mais caixas.

Because in Portuguese, the preposition normally stays before the relative word.

So:

• com quem falei = with whom I spoke

This is the standard pattern when the relative refers to a person:

• a pessoa com quem falei
• o amigo com quem saí

English often allows a preposition at the end, as in the tenant I spoke with, but Portuguese normally does not do that in standard usage.

Here, quem means whom or the person who, after a preposition.

In this sentence:

• A inquilina com quem falei = The tenant with whom I spoke

After prepositions such as com, de, para, por, Portuguese very often uses quem when talking about people:

• a pessoa de quem gosto = the person whom I like / the person I like
• o rapaz para quem escrevi = the boy to whom I wrote

Yes, you could say:

• A inquilina com a qual falei...

It is grammatically correct, but com quem falei is usually more natural when referring to a person.

So:

• com quem = very natural for people
• com a qual = correct, but often more formal or heavier

Because Portuguese often leaves out subject pronouns when the verb ending already shows who the subject is.

• falei = I spoke
• falaste = you spoke
• falou = he/she/you (formal) spoke

So falei already tells you the subject is I. You could say eu falei, but that usually adds emphasis, contrast, or clarity.

After querer when the same person wants to do something, Portuguese uses:

• querer + infinitive

So:

• quer pintar = wants to paint
• quer sair = wants to leave
• quer comprar = wants to buy

You do not conjugate the second verb here.

Only if the person who wants something and the person who does the action are different.

In your sentence, the tenant is the one who wants and the one who will paint, so Portuguese uses:

• quer pintar

If the meaning were The tenant wants someone else to paint the room, then Portuguese would use something like:

• A inquilina quer que pintem a sala
• A inquilina quer que eu pinte a sala

So:

• same subject → quer + infinitive
• different subject → often quer que + subjunctive

Because antes followed by a verb in the infinitive normally takes de.

So:

• antes de levar = before taking/carrying
• antes de sair = before leaving
• antes de comer = before eating

This is a fixed pattern in Portuguese:

• antes de + infinitive

By default, it is understood to be the same subject as the main clause: the tenant.

So the natural reading is:

• The tenant wants to paint the room before she takes/carries more boxes.

Portuguese often leaves the subject of the infinitive unspoken when it is the same as the subject of the main verb.

Levar usually means to take or to carry, depending on context.

In this sentence, levar mais caixas could be understood as:

• to carry more boxes
• to take more boxes
• sometimes even to bring in more boxes, depending on the situation and point of view

A useful basic contrast is:

• levar = take/carry away from a point of reference
• trazer = bring toward a point of reference

But in real usage, context matters a lot.

Portuguese uses definite articles more often than English.

So a sala is completely normal and usually means the room or the living room, depending on context.

In European Portuguese, sala often refers to the living room. If you just said pintar sala without the article, it would sound unnatural here.

Mais caixas means more boxes or additional boxes.

There is no article because the sentence is talking about an indefinite extra quantity, not specific boxes already identified one by one.

Compare:

• levar mais caixas = take/carry more boxes
• levar as caixas = take the boxes
• levar mais umas caixas = take a few more boxes

Yes.

• a inquilina = the female tenant
• o inquilino = the male tenant

The article and noun both show grammatical gender:

• a
  • inquilina
• o
  • inquilino

If the tenant’s sex is unknown or irrelevant, the form you choose depends on who the person is.

Because the sentence refers to two different time frames:

• falei = I spoke / I talked → that happened earlier
• quer = wants → that is true now

So the meaning is roughly:

• I already spoke to the tenant, and now she wants to paint the room before carrying more boxes.

This mix of tenses is very normal.

Yes, it is very natural.

The structure is:

• A inquilina = subject
• com quem falei = relative clause describing the tenant
• quer pintar a sala = main action
• antes de levar mais caixas = time phrase

So the sentence flows in a normal, standard European Portuguese way.