La professora vol que responguem avui i no demà.

Vol is the 3rd person singular present form of voler, meaning to want.

So:

• voler = to want
• vol = he/she wants

In this sentence, La professora vol... means The teacher wants...

Catalan normally uses vol que + subjunctive when one person wants someone else to do something.

So:

• La professora vol respondre = The teacher wants to answer
  (the teacher herself wants to answer)

• La professora vol que responguem = The teacher wants us to answer
  (the teacher wants another subject, namely us, to do it)

Here que introduces the subordinate clause, roughly like that in English, even though English often leaves that out or uses wants us to... instead.

Because after a verb of wanting, like vol, Catalan uses the subjunctive in the following clause when the subject changes.

Here the first subject is:

• La professora = the teacher

And the second subject is:

• responguem = we answer

Since the teacher wants us to do something, Catalan uses the subjunctive:

• vol que responguem

This is very common in Catalan after expressions of desire, doubt, emotion, or necessity.

Responguem is the 1st person plural present subjunctive form of respondre (to answer / to respond).

So it means:

• that we answer
• or in this sentence, simply we answer, inside a subjunctive clause

A quick mini-paradigm of the present subjunctive of respondre is:

• jo respongui
• tu responguis
• ell/ella respongui
• nosaltres responguem
• vosaltres respongueu
• ells/elles responguin

Because responem is the present indicative, not the subjunctive.

• responem = we answer / we are answering
• responguem = that we answer

After vol que, Catalan wants the subjunctive, so responguem is the correct form.

If you said La professora vol que responem, it would sound ungrammatical in standard Catalan.

This is part of the verb’s subjunctive pattern.

The infinitive is respondre, but in some forms the stem changes to respong-:

• responc
• respongui
• responguem

The gu is there so that the g keeps its hard sound before e:

• ge by itself could suggest a softer sound
• gue keeps the hard g sound

So responguem is both a grammatical verb form and a spelling pattern that preserves pronunciation.

Because Catalan often leaves subject pronouns out when the verb ending already makes the subject clear.

Responguem already tells you the subject is we.

So:

• que responguem = that we answer
• que nosaltres responguem = also possible, but more emphatic

Catalan does this much more often than English.

Because Catalan structures this idea differently.

English says:

• The teacher wants us to answer

Catalan says:

• The teacher wants that we answer
• La professora vol que responguem

So instead of using us as an object, Catalan uses a whole subordinate clause with que and a verb form that already shows we.

That is why you do not see a separate word corresponding directly to English us.

Yes. Professora is feminine, so it refers to a female teacher.

Compare:

• la professora = the female teacher
• el professor = the male teacher

The article la matches the feminine noun professora.

Here i no demà means and not tomorrow, giving a simple contrast: today, not tomorrow.

This works well because the sentence is basically:

• she wants it today
• and not tomorrow

Sinó is usually used after an explicit negation that corrects or replaces something:

• No demà, sinó avui = Not tomorrow, but today

So in this sentence, avui i no demà is natural and straightforward. If you wanted a slightly stronger contrast, you might also hear avui i no pas demà.

Yes, but the original order is very natural.

La professora vol que responguem avui i no demà is the neutral way to say it.

You can move things around for emphasis, for example:

• La professora vol que avui responguem i no demà
• Avui, la professora vol que responguem, no demà

But changing the order changes the focus slightly. The given sentence is the most standard and balanced version.

Because Catalan spelling rules require an accent on demà, but not on avui.

The accent in demà shows the stressed syllable:

• de-MÀ

By contrast, avui is written without an accent under normal spelling rules.

So the accent is not random; it follows Catalan accentuation rules. Even when two words are both very common time expressions, one may need a written accent and the other may not.

A practical pronunciation for learners is roughly:

• res-pon-GEM

More precisely, the stress is on the last syllable of the verb form:

• res-pon-GUEM

The gu keeps a hard g sound, so it is not pronounced like English j.

A rough English-friendly approximation would be:

• ress-pon-GHEM

The exact vowel sounds depend on dialect, but the important points are:

• the stress falls near the end
• the g is hard
• the ending clearly marks we in the subjunctive form