Learn French: Si le loyer était moins cher, j'aimerais que nous soyons colocataires. - If the rent was less expensive, I would like us to be flatmates.

Soyons is the present subjunctive form of être (to be) for nous. We must use the subjunctive here because the phrase j'aimerais que (I would like that) expresses a wish or desire, and there is a change of subject from I (j') to we (nous).

Is soyons a regular subjunctive conjugation?

Être is highly irregular. While most verbs in the subjunctive take an -ons ending for nous that looks exactly like the normal present tense, être completely changes its stem to soy-.

Why does the sentence use the imparfait (était) and then the conditional (aimerais)?

This is a classic hypothetical sentence structure. When you use si (if) to talk about an imagined situation in the present (the rent is not currently cheaper), you use the imparfait (était) in the if-clause, and the conditional (aimerais) for the result or consequence.

Why is there no article like des before colocataires?

In French, when you use the verb être followed by a noun that describes a person's status, profession, or relationship (like roommate, doctor, or student), you usually drop the article. So it is simply nous soyons colocataires instead of nous soyons des colocataires.