Quan em fa mal el coll, no vull parlar per telèfon.

Quan means when here. In a sentence like this, it often has the sense of whenever or when(ever) in English:

• Quan em fa mal el coll, no vull parlar per telèfon.
• When my throat/neck hurts, I don’t want to talk on the phone.

So this can describe a repeated situation, not just one single moment.

Literally, it is something like my neck/throat does pain to me or the neck/throat causes pain to me.

The structure is:

• em = to me
• fa = does / makes
• mal = pain / harm
• el coll = the neck / throat

Catalan often uses this pattern for physical pain:

• Em fa mal el cap = My head hurts.
• Em fan mal els peus = My feet hurt.

It is a very common and natural structure.

Em is an unstressed pronoun meaning to me.

In this expression, the pain is understood as affecting a person:

• em = to me
• et = to you
• li = to him/her
• ens = to us
• us = to you all
• els = to them

Examples:

• Em fa mal el coll. = My throat hurts.
• Et fa mal el coll? = Does your throat hurt?
• Li fa mal el coll. = His/Her throat hurts.

So em tells you who is experiencing the pain.

With body parts, Catalan usually prefers the definite article (el, la, els, les) rather than a possessive like my.

So Catalan says:

• Em fa mal el coll
  not usually
• Em fa mal el meu coll

This is similar to other Romance languages. Since em already tells you whose body is involved, adding meu is usually unnecessary.

The same happens in many everyday expressions:

• Em rento les mans. = I wash my hands.
• M’he fet mal al braç. = I hurt my arm.

It can cause some confusion for English speakers.

Coll literally means neck, but in sentences about pain it can sometimes be understood in a way that overlaps with English throat, depending on context.

However, if you specifically want to say throat in the medical or sore-throat sense, Catalan very often uses:

• gola = throat

For example:

• Em fa mal la gola. = My throat hurts.
• Tinc mal de coll. = I have a sore throat.

So in real life, learners should know that mal de coll is the standard expression for sore throat, even though coll by itself usually means neck.

Catalan has more than one way to talk about pain.

A very common everyday pattern is:

• fer mal = to hurt

So:

• Em fa mal el coll. = My neck/throat hurts.

There is also the verb doldre, which means to hurt, but it is less straightforward for learners because its forms are irregular and often feel more formal or less common in basic conversation.

For example:

• Em dol el coll = My neck hurts.

This is correct, but em fa mal el coll is often easier to learn first and is extremely common.

Because the thing causing the pain is singular: el coll.

Compare:

• Em fa mal el coll. = My neck/throat hurts.
• Em fa mal el braç. = My arm hurts.

But with a plural body part, Catalan uses plural:

• Em fan mal les cames. = My legs hurt.
• Em fan mal les dents. = My teeth hurt.

So the verb agrees with the thing that hurts.

After voler (to want), Catalan normally uses a bare infinitive, just like English:

• vull parlar = I want to speak
• vull menjar = I want to eat
• vull descansar = I want to rest

So:

• no vull parlar = I don’t want to talk

You do not add a after voler in this kind of structure.

As for parlar-ne, that would mean something like to talk about it, which is not the meaning here.

Per telèfon means by phone or on the phone.

The preposition per is used here to express the means or medium of communication. It is the normal Catalan expression:

• parlar per telèfon = to talk on the phone
• trucar per telèfon is less necessary because trucar already implies calling

English uses on the phone, but Catalan uses per telèfon.

Sometimes al telèfon appears in Catalan, but it usually has a different feel.

• parlar per telèfon = to talk by phone / on the phone
• estar al telèfon = to be on the phone

So in your sentence, per telèfon is the natural choice because it refers to the manner of speaking.

Because the sentence describes a general or repeated situation:

• Quan em fa mal el coll = When my throat/neck hurts
• no vull parlar per telèfon = I don’t want to talk on the phone

This is similar to English using the present for habits or repeated truths:

• When I’m tired, I go to bed early.

So the present tense here does not have to refer only to what is happening right now. It can describe what usually happens.

Yes. Catalan allows some flexibility.

Your sentence:

• Quan em fa mal el coll, no vull parlar per telèfon.

A very natural alternative is:

• No vull parlar per telèfon quan em fa mal el coll.

Both are correct. The version with Quan... first puts more emphasis on the condition or situation. The version with No vull parlar... first puts more emphasis on the main action.

Yes, absolutely. That is very natural, and for many learners it may even be easier to understand.

• tenir mal de coll = to have a sore throat

So:

• Quan tinc mal de coll, no vull parlar per telèfon.

This clearly means When I have a sore throat, I don’t want to talk on the phone.

Compared with em fa mal el coll, this version uses a fixed expression for sore throat. Both are good, but tinc mal de coll is especially useful to memorize as a set phrase.