Depois do banho, o pêlo do cão ficou tão macio que a criança não parava de lhe tocar.

Because do is the contraction of de + o.

So:

• depois do banho = after the bath
• o pêlo do cão = the fur of the dog / the dog's fur

Portuguese uses these contractions very regularly:

• de + o = do
• de + a = da
• em + o = no
• em + a = na

They are extremely common, and in normal writing you are expected to use them.

Here ficou means became or ended up being.

It is the pretérito perfeito form of ficar. In this sentence, it shows a change of state:

• o pêlo do cão ficou tão macio = the dog's fur became so soft

That is different from simply describing a state:

• estava macio = was soft
• ficou macio = became soft

So ficou is a very natural choice because the bath caused the fur to change.

Because macio agrees with o pêlo, which is masculine singular.

In Portuguese, adjectives usually agree in gender and number with the noun they describe:

• o pêlo macio = masculine singular
• a toalha macia = feminine singular
• os pêlos macios = masculine plural
• as mantas macias = feminine plural

Even though a criança appears later in the sentence and is feminine, macio is not describing a criança. It is describing o pêlo.

tão ... que means so ... that.

It is a very common structure in Portuguese:

• tão macio que... = so soft that...
• tão cansado que adormeceu = so tired that he fell asleep
• tão alto que toda a gente ouviu = so loud that everyone heard

So in your sentence:

• ficou tão macio que a criança não parava de lhe tocar

means the fur became soft to such an extent that the child kept touching it.

não parava de + infinitive means wouldn't stop + -ing or kept + -ing.

So:

• não parava de lhe tocar = wouldn't stop touching him/it / kept touching him/it

This is a very useful pattern:

• não parava de falar = wouldn't stop talking
• não parava de rir = couldn't stop laughing
• não parava de olhar = kept looking

Here parava is in the imperfect, which gives the idea of an ongoing or repeated action in the past.

The imperfect here shows a repeated or continuous past action.

Compare the feeling:

• não parou de tocar = did not stop touching / one completed event
• não parava de tocar = kept touching / ongoing, repeated, continuous

In this sentence, the imperfect fits well because it paints a scene: the child kept on touching the dog's fur again and again.

Here lhe refers most naturally to o cão, though in context the idea is really that the child kept touching the dog, especially its fur.

lhe is a clitic pronoun that often means:

• to him
• to her
• to it

But with some verbs, especially in real usage, the English translation may sound like a direct object. So lhe tocar here is understood as touch him/it.

This is one of those places where Portuguese and English do not line up neatly word-for-word.

With tocar, Portuguese often does not behave like English to touch.

In European Portuguese, when referring to a person or animal, you will often see or hear structures such as:

• tocar-lhe
• tocar no cão
• tocar na mão

So in this sentence, lhe tocar is a natural European Portuguese way of saying touch him/it.

For an English speaker, it helps to learn this as a usage pattern of tocar, rather than trying to match English grammar exactly.

Because lhe belongs to tocar, not to parava.

The structure is:

• parar de + infinitive

So the action being discussed is tocar, and lhe is the object of that infinitive:

• não parava de lhe tocar

In European Portuguese, this placement is very natural with prepositions plus infinitives.

Yes, but pêlo can be used as a collective or mass noun, much like fur in English.

So:

• o pêlo do cão = the dog's fur

You are not counting individual hairs. You are talking about the dog's coat or fur in general.

If you wanted to talk about individual hairs, you could use the plural:

• os pêlos do cão = the dog's hairs

But in this sentence, the singular is the most natural choice.

Good question. Pêlo is an older spelling.

Before the spelling reform, the circumflex in pêlo helped distinguish it from pelo, which can mean by the or through the and comes from por + o.

In current standard spelling, the noun is usually written pelo as well, without the circumflex. So today you will most often see:

• Depois do banho, o pelo do cão...

If you see pêlo, it is usually:

• an older spelling
• a conservative spelling choice
• or a text that keeps the old distinction for clarity

Yes. In European Portuguese, cão is the standard general word for dog.

That is worth noticing because English speakers often learn Brazilian Portuguese first, where cachorro is very common for dog.

In Portugal:

• cão = dog
• cachorro often means puppy or a young dog

So o cão sounds completely natural in Portugal.

These three words contain sounds that English speakers often find tricky.

• banho: the nh sounds like the ny in canyon, but smoother
• cão: the ão is nasal; there is no exact English equivalent, but it is a bit like saying cow through your nose
• lhe: the lh is a palatal sound, a bit like the lli in some pronunciations of million, though again there is no exact English match

A rough English-style approximation would be:

• banho ≈ BAH-nyoo
• cão ≈ something like cow with nasalisation
• lhe ≈ lyuh with a very short final vowel

The exact European Portuguese sounds are more reduced and tighter than these approximations, but they are a helpful starting point.