Learn Hardcore Portuguese (Portugal): O semáforo estava avariado, por isso chamámos novamente a polícia. - The traffic light was broken, so we called the police again.

Avariado is the past participle of the verb avariar, used as an adjective with estar to indicate that something is broken or malfunctioning. In this sentence, o semáforo estava avariado means “the traffic light was out of order.” Portuguese often uses the past participle as an adjective for states resulting from an action or defect.

Why estava (imperfect) and not a preterite like esteve?

The imperfect estava describes an ongoing or background state in the past (“it was in that condition for a while”). Using the preterite esteve avariado would sound more like a punctual event (“it was broken for a specific moment”), whereas estava avariado emphasizes duration or context.

What does por isso mean and how is it different from então?

Por isso literally means “because of that,” functioning as a coordinating conjunction for cause and effect (“therefore/so”).

Por isso tends to be a bit more formal or explicit.
Então also means “then” or “so,” but is more colloquial and can imply sequence rather than direct causation.
You could say então here, but por isso stresses the causal link.

Why is there an accent in chamámos?

In European Portuguese, the first-person plural preterite of regular -ar verbs is spelled chamámos (with an accent on the second “a”) to mark the stressed syllable. Without it, chamamos would be confused with the present tense “we call.” Brazilian Portuguese generally writes chamamos for both tenses and relies on context for interpretation.

What’s the difference between novamente, de novo, and outra vez?

All three mean “again,” but differ slightly in register:

Novamente: more formal or written.
De novo: common in speech, slightly informal.
Outra vez: very neutral, used both in writing and speaking.
You can swap them without changing the core meaning: chamámos de novo a polícia, chamámos outra vez a polícia, etc.

Why is a polícia in the singular with an article, and what exactly does it refer to?

A polícia is a collective noun referring to the police force as a whole. The definite article a specifies that you’re talking about “the police” (not any officer in general). If you meant “an officer,” you’d say um agente da polícia or um polícia (colloquially).

Could we use a clitic pronoun instead of repeating a polícia, like chamámo-la?

Yes, grammatically you could say chamámo-la (“we called it/her”). However, in modern spoken Portuguese (especially Portugal) it’s more natural to keep a polícia after the verb. Clitic enclisis (verb+pronoun) is common in formal or literary styles, but less so in everyday conversation.

Is the word order in chamámos novamente a polícia flexible?

Yes. In European Portuguese, you can place the adverb novamente before or after the verb:

Novamente chamámos a polícia.
Chamámos a polícia novamente.
The object a polícia stays right after the verb or pronoun cluster unless you rephrase with clitics or change style.

How might this sentence differ in Brazilian Portuguese?

A Brazilian speaker might say:
“O semáforo estava com defeito, então ligamos de novo para a polícia.”
Key differences:

com defeito or quebrado instead of avariado
ligamos para a polícia rather than chamámos a polícia
no accent on chamamos
use of então and de novo is more typical

Why is there a comma before por isso?

Por isso links two independent clauses: the cause (o semáforo estava avariado) and the effect (chamámos novamente a polícia). A comma is standard to mark that pause and make the sentence easier to read.