Learn Hardcore Portuguese (Portugal): Um dia hei de falar português com muita confiança. - One day I will speak Portuguese with a lot of confidence.

hei de falar – slightly literary or “elevated” in tone in Portugal, often with a nuance of eventuality / destiny / hope.
- Um dia hei de falar português… → Someday, I shall end up speaking Portuguese…
vou falar – the most common everyday way to talk about the future in speech, like English “I’m going to speak” / “I’ll speak”.
- Um dia vou falar português com muita confiança.
falarei – the synthetic future tense; in Portugal it tends to sound more formal or written, or used in very deliberate / emphatic speech.
- Um dia falarei português com muita confiança.

In casual European Portuguese conversation, vou falar is usually the default. Hei de falar adds that “one day, I’ll get there” feeling.

Is hei de still common in European Portuguese, or does it sound old-fashioned?

In Portugal, hei de is still used and understood by everyone, but:

It sounds a bit literary, poetic, or reflective, especially in careful speech or writing.
In everyday casual speech, people more often say vou falar.

So Um dia hei de falar português… is perfectly natural, especially in writing or when you want to sound a bit thoughtful or expressive, not stiffly old-fashioned.

Can I change the word order, e.g. say Hei de falar português um dia instead?

Yes, several word orders are possible and grammatical:

Um dia hei de falar português com muita confiança.
Hei de falar português com muita confiança um dia.
Um dia, hei de falar português com muita confiança.

Putting Um dia at the beginning is very natural and emphasizes “one day (in the future)”. Moving um dia to the end is also okay but feels a bit less standard in this kind of aspirational sentence.

What you can’t do is break up the verb phrase in an odd way, e.g.:

✗ Hei de um dia falar português… (understandable, but clumsy here)

Why is there no article: why falar português and not falar o português?

In Portuguese, when you talk about speaking / learning / studying a language in general, you usually omit the article:

falar português / inglês / francês – to speak Portuguese / English / French
aprender português – to learn Portuguese
saber português – to know Portuguese

You would use the article if you were referring to the language as an object or topic, not as a skill:

Gosto do português falado em Portugal. – I like the Portuguese (language) spoken in Portugal.
O português é uma língua românica. – Portuguese is a Romance language.

In Um dia hei de falar português…, you’re talking about the ability, so no article is correct.

Why is português not capitalized, even though Portuguese is in English?

In Portuguese, names of languages and nationalities are not capitalized, unless they start the sentence:

português, inglês, espanhol, francês
sou português – I am Portuguese.
falo português – I speak Portuguese.

So português is correctly written with a lowercase p in the sentence:

Um dia hei de falar português com muita confiança.

What is português grammatically here: an adjective or a noun? Why not a língua portuguesa?

In this sentence, português functions as a noun meaning “the Portuguese language”:

falar português – to speak Portuguese (the language)

You could explicitly say:

Um dia hei de falar a língua portuguesa com muita confiança.

…but that sounds very formal / bookish and is not how people normally talk. Using português by itself as a noun is the natural everyday choice.

Why do we say com muita confiança and not something like muito confiante?

com muita confiança = “with a lot of confidence” (noun phrase)
muito confiante = “very confident” (adjective phrase)

In Portuguese, when describing how someone speaks, falar com (muita) confiança is very idiomatic:

Ele fala com confiança. – He speaks with confidence.
Ela fala com muita confiança em público. – She speaks with great confidence in public.

You can say:

Um dia vou estar muito confiante a falar português.

but this slightly switches focus to you being confident as a general state, while falar português com muita confiança focuses on the manner of speaking. Both are correct; the original is just more idiomatic for “speak confidently”.

Can I omit muita and just say com confiança? Does it change the meaning?

Yes, both are correct, with a small nuance:

com confiança – with confidence
com muita confiança – with a lot of / great confidence

So:

Um dia hei de falar português com confiança. – One day I will speak Portuguese with confidence.
Um dia hei de falar português com muita confiança. – One day I will speak Portuguese with a lot of confidence / very confidently.

The version with muita sounds a bit stronger and more emphatic.

Does Um dia mean “someday (I don’t know when)” or “one specific day”?

In this context, Um dia means “someday / one day (in the future, unspecified)” — just like in English in a sentence like:

One day I’ll speak Portuguese confidently.

It does not refer to a specific date here.

If you wanted to be very clearly vague, you could also say:

Algum dia hei de falar português com muita confiança.

But Um dia… is already the standard idiomatic way to express “one day / someday” in this aspirational sense.

Should there be a comma after Um dia?

Both are accepted, but the comma is common and stylistically neat:

Um dia, hei de falar português com muita confiança.
Um dia hei de falar português com muita confiança.

In short, adding the comma is often preferred in writing because Um dia is an introductory time phrase, but omitting it is not “wrong” and is quite frequent in informal text.

Where would I put bem if I want to say “speak Portuguese well and confidently”?

Common, natural options include:

Um dia hei de falar bem português, com muita confiança.
Um dia hei de falar português bem, com muita confiança.
Um dia hei de falar português muito bem e com muita confiança.

Some notes:

bem can go before or after português; both are heard.
bem português can also be read as “very Portuguese” in some contexts, but with falar bem português the meaning “speak Portuguese well” is clear.
Adding muito bem makes the “well” part stronger: very well.

What’s the difference between falar português and falar em português?

Both exist, but they’re used slightly differently:

falar português – emphasizes the ability to speak the language.
- Aprendi a falar português. – I learned to speak Portuguese.
falar em português – emphasizes the language as the medium you’re using right now.
- Podemos falar em português? – Can we speak in Portuguese? (i.e., can we use Portuguese instead of another language?)

In your sentence, you’re talking about the ability and confidence in using the language, so falar português com muita confiança is the natural choice.