Learn Hardcore Portuguese (Portugal): A mãe tentou convencer o filho a deitar‑se mais cedo. - The mother tried to convince her son to go to bed earlier.

Para + infinitive is also possible in Portuguese, but it usually expresses purpose / goal (in order to), not this specific verb pattern of “convince someone to do something”.

Veio cedo para estudar. = He came early (in order) to study.

Here we are not expressing purpose directly; we’re expressing what the son is being convinced to do, so the normal construction is convencer alguém a + infinitivo, not convencer alguém para + infinitivo.

What does se in deitar-se do, and why is it attached with a hyphen?

Se is a reflexive pronoun.

deitar = to lay, to lay something down
deitar-se = to lie down / to go to bed (literally “to lay oneself down”)

In European Portuguese, after a preposition like a, the pronoun normally goes after the infinitive verb, joined with a hyphen:

a deitar-se
sem se deitar
para se levantar

So in this sentence, deitar-se means “for him to go to bed / lie down”, and the se is attached to deitar with a hyphen because that’s the standard placement after a preposition + infinitive in European Portuguese.

Could we say a se deitar instead of a deitar-se?

In European Portuguese, the normal (and expected) form after a + infinitive is a deitar-se (pronoun after the verb).

A mãe tentou convencer o filho a deitar-se mais cedo. ✅

A se deitar is typical of Brazilian Portuguese in speech:

A mãe tentou convencer o filho a se deitar mais cedo. (Brazilian style)

So:

In Portugal: a deitar-se
In Brazil: in standard writing both are technically possible, but a se deitar is what you most often hear.

Why is it o filho and not seu filho (“her son”) or just filho?

In Portuguese, possession with close family members is usually clear from context, so speakers often use the definite article + noun:

A mãe falou com o filho. = The mother spoke with her son.

Using seu filho is not wrong, but:

It can sound a bit heavier or more formal.
In some contexts seu can be ambiguous (it might mean “his” / “their”).

Just filho without an article would be strange here. In Portuguese, singular countable nouns almost always appear with an article or another determiner:

O filho, um filho, seu filho, etc.

So o filho is the most natural and neutral way to say her son in this sentence.

Does o filho mean specifically a son (male child), or could it be any child?

O filho is specifically masculine: son.

o filho = the son
a filha = the daughter
os filhos = children (can mean “sons” or “sons and daughters”)
as filhas = daughters

So in this sentence we are clearly talking about a boy (her son).
For a daughter, you would say:

A mãe tentou convencer a filha a deitar-se mais cedo.

Could we say convencer ao filho instead of convencer o filho?

No. With convencer alguém, the person is a direct object, so there is no preposition:

convencer o filho ✅
convencer ao filho ❌

You only use a preposition a before the infinitive:

convencer o filho a deitar-se (convince the son to go to bed)

Why is it convencer alguém a fazer but convencer alguém de/que uma coisa é verdade?

Portuguese makes a distinction like this:

Convencer alguém a + infinitive
= convince someone to do something
- Convencer o filho a deitar-se.
Convencer alguém de / de que / que + clause
= convince someone of / that something is true
- Convencer o filho de que dormir cedo é importante.
- Convencer o filho que dormir cedo é importante.

So:

a + infinitive for actions (do something)
de / (de) que + clause for beliefs / facts (believe something)

Why is the verb deitar-se in the infinitive, not conjugated (like que se deitasse)?

The pattern convencer alguém a + infinitivo is the normal and simplest construction:

A mãe tentou convencer o filho a deitar-se mais cedo. ✅

You could also say:

A mãe tentou convencer o filho a que se deitasse mais cedo.
(using the subjunctive se deitasse)

This version is more formal / literary and less common in everyday speech.

So the infinitive after convencer alguém a is:

More natural
Shorter and simpler
Absolutely standard in both spoken and written language

What is the difference between deitar-se, ir para a cama and adormecer?

They describe different stages of “going to bed”:

deitar-se = to lie down / to get into bed
- Physical action of lying down.
ir para a cama = to go to bed (literally “go to the bed”)
- Movement towards bed; implies getting ready to sleep.
adormecer = to fall asleep
- The moment when you actually start sleeping.

In this sentence, a deitar-se mais cedo focuses on the habit of going to bed (lying down) earlier, not specifically on the moment of falling asleep.

Could we also say pôr o filho na cama mais cedo with a similar meaning?

Yes, but the focus is slightly different:

convencer o filho a deitar-se mais cedo
- Emphasis on persuading the child to cooperate and go to bed by himself.
pôr o filho na cama mais cedo
- Literally “to put the son in bed earlier”; emphasizes the parent’s action of putting him to bed, not the persuasion.

Both can be used about bedtime routines, but convencer o filho a deitar-se highlights the convincing / negotiation aspect.

What exactly does mais cedo mean here?

Mais cedo is “earlier” in the sense of earlier than usual or earlier than some reference time.

cedo = early
mais cedo = earlier

In this sentence, mais cedo implies:

earlier than he normally goes to bed
or earlier than the mother considers acceptable

You could make it explicit, if needed:

… a deitar-se mais cedo do que de costume.
(= to go to bed earlier than usual)

Why is the tense tentou (preterite) and not tentava (imperfect)?

Both are possible, but they give different nuances:

tentou (pretérito perfeito)
- A completed attempt, seen as a single event in the past.
- A mãe tentou convencer o filho… = She tried (at that point / on that occasion).
tentava (pretérito imperfeito)
- A repeated or ongoing attempt in the past.
- A mãe tentava convencer o filho a deitar-se mais cedo.
  = She used to try / was trying (habitually or over some period).

In isolation, tentou is the default if you’re talking about one specific attempt or just stating the fact that she tried.

How would a Brazilian usually say this sentence? Is there any difference?

The sentence is perfectly correct in Brazilian Portuguese as-is, but everyday Brazilian speech would most often change the pronoun position:

A mãe tentou convencer o filho a se deitar mais cedo.

Main differences:

European Portuguese: a deitar-se (pronoun after the infinitive)
Brazilian Portuguese (spoken): a se deitar (pronoun before the infinitive)

The rest (A mãe tentou convencer o filho / mais cedo) is the same in both varieties.

How do you pronounce filho, tentou, and deitar-se in European Portuguese?

Approximate indications (not exact IPA):

filho:
- fi like “fee” but shorter
- lh like “ly” in “million”
- o very reduced, almost like uh
- Roughly: “FEEL-yuh” (but shorter and more compressed)
tentou:
- ten with nasal e (like French vin, but with e)
- tou like “toh”
- Roughly: “ten-TOH” (with a nasal first syllable)
deitar-se:
- dei like “day”
- tar almost “tarsh” (final r often very soft in Portugal)
- se very reduced, like “suh”
- Roughly: “day-TAR-suh”, but with a softer, more reduced final syllable.

For accurate sounds, you’d really need audio, but these approximations give you a basic idea.

Why is there no comma before a deitar-se mais cedo?

In Portuguese, we do not usually separate with a comma the infinitive complement governed by a verb like tentar / convencer / desejar / prometer, etc.

Tentou convencer o filho a deitar-se mais cedo. ✅
Tentou convencer o filho, a deitar-se mais cedo. ❌

The whole “convencer o filho a deitar-se mais cedo” functions as one verb phrase, so we keep it together without commas.