Jo li dic que, si tenim temps, després podem mirar l'exposició i anar a la llibreria.

Usually, no. In Catalan, subject pronouns are often omitted because the verb ending already shows who the subject is.

So:

• Jo li dic... = I tell him/her...
• Li dic... means the same thing in most contexts.

Jo is included for emphasis, contrast, or clarity. For example, it can suggest I’m the one saying this or contrast with someone else.

Li is an indirect object pronoun. In this sentence, it means to him, to her, or sometimes to you (formal singular), depending on context.

So:

• Jo li dic... = I tell him/her...
• literally: I to-him/to-her say...

Catalan uses these object pronouns very frequently, often where English just uses a normal object after the verb.

Because dir (to say / to tell) is irregular in the present tense.

Present tense of dir:

• jo dic
• tu dius
• ell/ella diu
• nosaltres diem
• vosaltres dieu
• ells/elles diuen

So dic is simply the correct 1st person singular present form: I say / I tell.

Que introduces a subordinate clause, just like that in English.

• Jo li dic que... = I tell him/her that...

In English, that is often optional:

• I tell him that we have time
• I tell him we have time

In Catalan, que is normally used in this structure.

This is a very common learner question.

• si (no accent) = if
• sí (with accent) = yes

In your sentence:

• si tenim temps = if we have time

So the version here must be si without an accent.

Both are present indicative forms:

• tenim = we have
• podem = we can

Catalan often uses the present tense in places where English also uses the present:

• si tenim temps = if we have time
• després podem... = afterwards we can...

These are forms of:

• tenir → tenim
• poder → podem

Because after si meaning if, Catalan normally uses the present indicative when referring to a real future possibility.

So:

• si tenim temps = if we have time not
• if we will have time

This is actually similar to natural English:

• English usually says If we have time, we’ll go not If we will have time...

So Catalan and English work similarly here.

Després means afterwards / later.

In your sentence:

• després podem mirar... = afterwards we can look at...

It often has flexible placement. For example:

• Després podem mirar l'exposició...
• Podem després mirar l'exposició... (less common / more marked)
• Podem mirar l'exposició després... (can work too, depending on meaning)

The position in your sentence is very natural.

Because they depend on podem (we can).

After a modal verb like poder, the next verb is usually in the infinitive:

• podem mirar = we can look at
• podem ... anar = we can ... go

This is similar to English:

• we can look
• we can go

So mirar and anar are not conjugated because podem is already the conjugated verb.

Because one conjugated modal verb can govern two infinitives joined by i (and).

So:

• podem mirar l'exposició i anar a la llibreria means
• we can look at the exhibition and go to the bookshop

Catalan does not need to repeat podem, just as English does not need to repeat can:

• We can visit the museum and go for coffee

You could repeat it for emphasis, but it is unnecessary:

• després podem mirar l'exposició i podem anar a la llibreria

Because la becomes l' before a vowel sound. This is called elision.

• la exposició → l'exposició

This is very common in Catalan:

• l'escola
• l'hora
• l'amiga

So l'exposició is simply the normal form of the exhibition.

The verb anar means to go, and it normally takes the preposition a before a destination.

• anar a Barcelona = to go to Barcelona
• anar a casa = to go home
• anar a la llibreria = to go to the bookshop

So the a here means to.

No — this is an important false friend.

• llibreria = bookshop / bookstore
• biblioteca = library

So:

• anar a la llibreria = to go to the bookshop not
• to go to the library

Because si tenim temps is an inserted conditional clause:

• Jo li dic que, si tenim temps, després podem...

The commas help separate that condition from the rest of the sentence.

Without the inserted clause, the structure is:

• Jo li dic que després podem mirar l'exposició...

Then si tenim temps is added parenthetically:

• Jo li dic que, si tenim temps, després podem...

In writing, this punctuation is very natural and helps readability.

Yes, Catalan word order is somewhat flexible, though some versions sound more natural than others.

For example, these are possible:

• Jo li dic que, si tenim temps, després podem mirar l'exposició i anar a la llibreria.
• Li dic que, si tenim temps, després podem mirar l'exposició i anar a la llibreria.
• Si tenim temps, li dic que després podem mirar l'exposició i anar a la llibreria.
  This changes the focus a bit.

The original order is very natural if the main point is I tell him/her that later, if we have time, we can...

Both can relate to seeing, but they are not identical.

• mirar = to look at, to watch
• veure = to see

In this sentence:

• mirar l'exposició suggests looking at / visiting the exhibition
• veure l'exposició could also work in some contexts, but it feels slightly different

With exhibitions, museums, shows, and displays, mirar can sound very natural because it emphasizes the act of looking at what is there.

In this sentence, dir is best translated as tell because there is an indirect object:

• Jo li dic que... = I tell him/her that...

But dir can also correspond to say in other contexts:

• Diu que vindrà. = He says that he’ll come.
• Què has dit? = What did you say?

So dir covers both say and tell, depending on the structure.

A very natural everyday version would be:

• Li dic que, si tenim temps, després podem mirar l'exposició i anar a la llibreria.

This is probably what you would hear most often in normal conversation, unless the speaker wants to stress jo.