O filhote está com sono.

Filhote usually means a baby animal, young animal, or cub/puppy/kitten, depending on context. It is a general word, not a species-specific one.

Examples:

• o filhote de cachorro = the puppy
• o filhote de gato = the kitten
• o filhote de leão = the lion cub

By itself, o filhote means the baby animal / the little one.

Because filhote is grammatically masculine in Portuguese, so it takes o in the singular:

• o filhote = the baby animal
• os filhotes = the baby animals

This is grammatical gender, not necessarily biological sex. Even if the animal is female, people may still use o filhote unless they specifically want to mark it as female in some other way.

Portuguese has two common verbs for to be: ser and estar.

Here, está is used because being sleepy is seen as a temporary state, not a permanent characteristic.

• estar com sono = to be sleepy
• ser would not be natural here

So:

• O filhote está com sono. = The baby animal is sleepy.

This is just the normal Portuguese expression. Literally, com sono means with sleep, but idiomatically it means sleepy.

Portuguese often uses estar com + noun for physical states or sensations:

• estar com fome = to be hungry
• estar com sede = to be thirsty
• estar com medo = to be afraid
• estar com sono = to be sleepy

So even though it sounds different from English, it is a very common and natural structure.

Sono is a noun. It usually means sleepiness, drowsiness, or sleep in the sense of the need for sleep.

So in this sentence:

• com sono = sleepy / feeling sleepy

It is not usually the same as the English noun sleep in every context. For example:

• Estou com sono. = I’m sleepy.
• O sono é importante. = Sleep is important.

Yes, but it means something slightly different.

• O filhote está com sono. = The baby animal is sleepy right now.
• O filhote é sonolento. = The baby animal is sleepy by nature / tends to be sleepy / is drowsy.

So está com sono describes a current condition, while é sonolento sounds more like a general trait.

Not always, but in this sentence it sounds natural and normal.

• O filhote está com sono. = The baby animal / the puppy is sleepy.

If you say just Filhote está com sono, it may sound incomplete or unusual in standard Portuguese unless it is being used in a special context, like calling the animal Filhote as a name or speaking in a very informal, abbreviated style.

Portuguese uses definite articles more often than English does.

A simple pronunciation guide for Brazilian Portuguese is:

oo feel-YO-chee es-TAH kohng SOH-noo

A few notes:

• lh in filhote sounds like the lli in million for many English speakers.
• te at the end of filhote in Brazil often sounds like chee.
• está has stress on the last syllable: es-TÁ.
• sono has stress on the first syllable: SO-no.

This is the normal Portuguese order:

subject + verb + complement

• O filhote = subject
• está = verb
• com sono = complement

It works very much like:

• O menino está cansado. = The boy is tired.
• A menina está com fome. = The girl is hungry.

So the sentence structure is straightforward and very common.

The plural would be:

Os filhotes estão com sono.

Changes:

• o → os
• filhote → filhotes
• está → estão

com sono stays the same.

Usually filhote refers to an animal, especially a young one. For a human child, Portuguese normally uses words like:

• bebê = baby
• criança = child
• menino/menina = boy/girl

However, filhote can sometimes be used affectionately for a person, especially in family speech or playful language. In normal literal use, though, learners should think of it mainly as young animal.

No. Estar com sono is standard Portuguese and is used in Brazil and elsewhere in the Portuguese-speaking world.

What may differ a bit is pronunciation, but the expression itself is widely understood and standard.

You can understand it word-for-word like this:

• O = the
• filhote = baby animal / young one
• está = is
• com = with
• sono = sleep / sleepiness

So literally: The baby animal is with sleep.

But that is not natural English. The correct translation is The baby animal is sleepy or The puppy is sleepy, depending on context.