Ell està segur?

Yes. Catalan often drops subject pronouns because the verb ending already tells you the person and number.

So both of these are possible:

• Està segur?
• Ell està segur?

Including ell usually adds emphasis, contrast, or extra clarity, as in Is he sure? rather than someone else.

Because Catalan normally uses estar with segur when it means sure/certain.

• estar segur = to be sure / to be certain

So:

• Ell està segur? = asking about his certainty

Using ser here would not be the normal way to say that someone feels certain about something.

In Catalan, yes/no questions often use the same word order as statements. The difference is mainly shown by:

• intonation in speech
• the question marks in writing

So:

• Ell està segur. = statement
• Ell està segur? = question

Unlike English, Catalan does not usually invert the subject and verb here.

Yes, very naturally:

• Està segur?

This is often the most natural version if it is already clear who you are talking about. Catalan frequently prefers the version without the subject pronoun unless you want emphasis.

The accent mark shows the stressed syllable and is part of the correct spelling.

• està is pronounced roughly es-TA

The accent helps distinguish it from other written forms and tells you that the stress falls on the last syllable.

Because segur is an adjective, and adjectives in Catalan agree with the person they describe.

Here, ell is masculine singular, so the adjective is:

• segur

Compare:

• Ell està segur? = masculine singular
• Ella està segura? = feminine singular
• Ells estan segurs? = masculine plural or mixed group
• Elles estan segures? = feminine plural

It is an adjective. More specifically, it is a predicate adjective, because it comes after the verb estar and describes the subject.

So in Ell està segur?:

• ell = subject
• està = verb
• segur = adjective describing ell

Yes. Depending on context, segur can also mean safe or secure. But in the pattern estar segur, when talking about a person’s opinion or certainty, it usually means sure/certain.

So in this sentence, the natural reading is about certainty, not physical safety.

Yes. A very common spoken alternative is:

• Que està segur?

That initial que can help mark the sentence as a question in conversation, especially in speech. It does not change the basic meaning.

So you may hear both:

• Està segur?
• Que està segur?
• Ell està segur?

All are possible, with slightly different emphasis depending on context.