Learn Hardcore Portuguese (Brazil): Eu tenho guardado dinheiro porque quero viajar com meu filho para as montanhas no próximo ano. - I have been saving money because I want to travel with my son to the mountains next year.

Ter + past participle → tenho guardado
This is the present perfect and usually means an action that has been repeated or ongoing up to now.
In this sentence it means something like “I have been saving money (regularly, over time).”
Estar + gerund → estou guardando
This is the present continuous, focusing more on what is happening around now or in a limited period:
“I am (currently) saving money.”
Ter + gerund (tenho guardando) is wrong in standard Portuguese.

So tenho guardado is correct and chosen here to emphasize that saving has been happening over a period of time, not just right now.

Does tenho guardado dinheiro mean “I have been saving money” or “I have saved money”?

In Brazilian Portuguese, eu tenho guardado dinheiro is usually closer to:

“I have been saving money” (repeated/ongoing action over time)

The Portuguese present perfect often implies repetition or continuity up to the present, more like English present perfect continuous.

If you wanted a more “completed” idea (“I have saved some money already”), Brazilians very often use a simple past:

Eu já guardei dinheiro. – “I’ve already saved money.”

Could I just say Eu guardo dinheiro instead of Eu tenho guardado dinheiro?

You can, but the nuance changes:

Eu guardo dinheiro.
→ “I save money.”
This sounds like a general habit or characteristic (I’m the kind of person who saves money).
Eu tenho guardado dinheiro.
→ “I have been saving money.”
This points to an activity over a recent period, connected to now, usually with some specific purpose (here, the trip).

Both are possible, but tenho guardado fits especially well when you want to connect your ongoing saving to this specific future trip.

What’s the difference between guardar and economizar when talking about money?

Both can relate to money, but they’re not identical:

guardar dinheiro
Literally “to keep/put away money”. Commonly used to mean “to save money (put it aside, not spend it).”
economizar dinheiro
“To economize money”, to save by spending less, cutting expenses, being economical.

In everyday Brazilian Portuguese:

Estou guardando dinheiro para viajar.
Estou economizando dinheiro para viajar.

Both are fine and often interchangeable.
Guardar sounds a bit more like “setting money aside”; economizar highlights the idea of being frugal / cutting costs.

Why is it porque (one word) and not por que (two words) here?

In the sentence, porque introduces a reason:

...tenho guardado dinheiro porque quero viajar...
→ “…I have been saving money because I want to travel…”

Rules of thumb:

porque (one word)
→ used in answers and clauses of reason/cause: “because”
por que (two words)
→ used mainly in questions: “why”
e.g. Por que você está guardando dinheiro? – “Why are you saving money?”

Since we’re giving the reason (not asking), we use porque.

Can I omit eu and just say Tenho guardado dinheiro porque quero viajar…?

Yes.

Portuguese verb endings already show the subject, so pronouns like eu (I), você (you), etc., can often be dropped:

Tenho guardado dinheiro porque quero viajar…

This is natural and correct.
Using eu can add a bit of emphasis or clarity, especially in speech or when contrasting with another person, but grammatically it’s optional here.

Why is it com meu filho and not com o meu filho?

In Brazilian Portuguese, both are possible:

com meu filho
com o meu filho

Differences:

In Brazil, leaving out the article (o, a, os, as) with possessives is very common and sounds completely natural:
meu filho, minha mãe, meus amigos, etc.
In European Portuguese, using the article is more common: com o meu filho.

In Brazil, com meu filho is slightly more direct and a bit more informal/neutral; com o meu filho can feel a little more formal or emphatic, but both are correct.

Does filho mean “son” or can it also mean “child”?

Filho by default means “son” (male child).
Filha means “daughter” (female child).

Sometimes filho can be used in a more generic way (e.g. religious language), but in everyday use:

meu filho – my son
minha filha – my daughter
meus filhos – my children / my sons (plural, general)
minhas filhas – my daughters

Why is the preposition para used in viajar com meu filho para as montanhas instead of a or nas?

The choice depends on what you want to express:

para
- place → destination, “to”:
  viajar para as montanhas – “to travel to the mountains”
a
- place (e.g. viajar à França) also can mean “to”, but with montanhas, para is far more natural in Brazilian Portuguese.
nas montanhas = “in the mountains / in the mountain region”
viajar nas montanhas would suggest traveling in/through the mountains, not necessarily going to them as a destination.

So viajar para as montanhas is the standard way to say “travel to the mountains.”

Why is it as montanhas and not just para montanhas?

In Portuguese, place nouns usually take an article:

a montanha – the mountain
as montanhas – the mountains

Saying para montanhas (without article) is unusual and sounds incomplete.
We almost always say:

para a praia – to the beach
para a cidade – to the city
para as montanhas – to the mountains

The article as is the plural feminine definite article (“the”), agreeing with montanhas (feminine plural).

Why is it no próximo ano and not just próximo ano?

No próximo ano literally means “in the next year”:

em (in) + o próximo ano (the next year) → no próximo ano (contraction)

You can say simply próximo ano:

Eu vou viajar próximo ano.

This is understood and used, especially in less formal speech, but:

no próximo ano is a bit more explicit and very common in both speech and writing.
It sounds smoother and more idiomatic in many contexts.

So both work; no próximo ano is slightly more natural in many neutral sentences.

Is there a difference between no próximo ano and no ano que vem?

Yes, but the meaning is practically the same:

no próximo ano – literally “in the next year”
no ano que vem – “in the coming year / the year that is coming”

Both mean “next year”.
Stylistically:

no próximo ano – a bit more formal/neutral, good in writing or careful speech.
no ano que vem – very common in everyday Brazilian speech, sounds a bit more colloquial and conversational.

How would I make this sentence negative or turn it into a yes/no question?

Negative: place não before the main verb phrase.

Eu não tenho guardado dinheiro porque quero viajar com meu filho para as montanhas no próximo ano.
→ “I haven’t been saving money because I want to travel…”

Yes/no question: in Brazilian Portuguese, word order usually stays the same; you just use a questioning intonation (and possibly a question mark in writing):

Você tem guardado dinheiro porque quer viajar com seu filho para as montanhas no próximo ano?
Using eu:
Eu tenho guardado dinheiro porque quero viajar com meu filho para as montanhas no próximo ano? (sounds like you’re double-checking or surprised)

There’s generally no inversion like in English (“Have you…?”).

How are tenho and filho pronounced, especially the nh and lh?

Both use two important Portuguese consonants:

nh in tenho → similar to the “ny” in “cañon” (Spanish) or “onion” (the ny sound):
tenho ≈ TE-nyo (with nasal sound)
lh in filho → similar to the “ll” in Spanish “pollo” or the “lli” in English “million” (depending on accent):
filho ≈ FEE-lyo

So:

tenho: [ˈtẽ.ɲu]
filho: [ˈfi.ʎu]

Practicing nh (as in banho, tenho, vinho) and lh (as in filho, olho, velha) will help your pronunciation sound much more natural.