Learn Hardcore Portuguese (Portugal): Hoje decidi pôr um limite claro ao tempo de ecrã para melhorar o sono. - Today I decided to set a clear limit on screen time to improve my sleep.

pôr (with ^) is the verb “to put / to set”.
- Example: pôr um limite = to set a limit.
por (no accent) is a preposition, usually meaning “by / through / for / because of”.
- Example: por causa do sono = because of sleep.

In Hoje decidi pôr um limite…, you need a verb after decidi, so it must be pôr (infinitive verb), not the preposition por.

The accent is kept in modern spelling precisely to distinguish the verb pôr from the preposition por.

Why is the adjective after the noun (um limite claro) and not before it (um claro limite)?

In Portuguese, adjectives normally come after the noun:

um limite claro = a clear limit (neutral, normal order)

Putting claro before the noun ( um claro limite ) is possible but sounds literary or emphatic, and it can feel a bit unusual in everyday speech.

So:

um limite claro – natural, standard way to say “a clear limit”
um claro limite – more stylistic, rhetorical; you’d find it in speeches, literature, or for special emphasis.

For everyday European Portuguese, um limite claro is the normal and most idiomatic choice.

Why is it ao tempo de ecrã and not no tempo de ecrã or para o tempo de ecrã?

Ao is a contraction of a + o (“to/on + the”), and here it means “on / to / for” in the sense of imposing something on something:

pôr um limite ao tempo de ecrã
= to put/set a limit on screen time.

Alternatives:

no tempo de ecrã (em + o) = “in the screen time / during screen time” – this sounds wrong here, because you are not inside the time, you’re limiting it.
para o tempo de ecrã (for screen time) would sound like the limit is for the benefit of screen time, which is not the intended meaning.

The usual pattern with pôr um limite is:

pôr um limite a algo
→ hence pôr um limite claro ao tempo de ecrã.

What’s the difference between ecrã and tela?

Both mean “screen”, but:

In Portugal, people normally say ecrã.
- Example: tempo de ecrã = screen time.
In Brazil, people normally say tela.
- Example: tempo de tela = screen time.

Other details about ecrã (European Portuguese):

It’s masculine: o ecrã, os ecrãs.
Pronunciation: roughly eh-KRAHN (final ã is nasal).

So in European Portuguese, tempo de ecrã is the natural expression.

Why is there no eu in Hoje decidi pôr…? Could I say Hoje eu decidi pôr…?

Portuguese often omits subject pronouns because the verb ending already shows who the subject is.

decidi can only be “I decided” in this context, so eu is not needed.
Hoje decidi pôr… is perfectly natural and common.

You can say Hoje eu decidi pôr…, but then eu adds a bit of emphasis, like:

“I (as opposed to someone else) decided today…”
or “Today I decided (finally, or after some time)…”

Neutral, everyday version: Hoje decidi pôr um limite claro…

Could I say Hoje decidi limitar o tempo de ecrã instead? Does it change the meaning?

Yes, you can say:

Hoje decidi limitar o tempo de ecrã para melhorar o sono.

The meaning is very close. The nuance:

pôr um limite claro ao tempo de ecrã
– focuses on the limit as a concrete thing (a specific rule or boundary).
limitar o tempo de ecrã
– focuses more on the action of reducing/restricting the screen time.

Both are natural in European Portuguese; your original version is slightly more “structured” or formal, but both are good.

Why is it para melhorar o sono and not para dormir melhor or para melhorar o meu sono?

All three are possible, but they have slightly different flavours:

para melhorar o sono
- Literally: in order to improve (the) sleep.
- Refers to sleep in general / my sleep as a habit.
- Portuguese often uses o with abstract nouns and bodily functions:
  - o sono, a saúde, a memória.
para dormir melhor
- Literally: in order to sleep better.
- Very common and a bit more colloquial / direct.
- Hoje decidi pôr um limite claro ao tempo de ecrã para dormir melhor sounds very natural.
para melhorar o meu sono
- Literally: to improve my sleep.
- Grammatically fine, but o sono already implies “my sleep” in this context.
- Adding meu emphasizes that it’s specifically my sleep, which isn’t really needed here.

So the original para melhorar o sono is correct and idiomatic, and para dormir melhor is also an excellent alternative.

Why is um limite indefinite (um), but o sono uses the definite article (o)?

The articles match how specific / general the nouns are:

um limite claro
- um = “a / one” (indefinite).
- You’re introducing a new, not-yet-specified limit. You haven’t defined exactly what it is yet.
o sono
- o = “the” (definite), but in Portuguese it’s also used for general concepts / abstractions.
- o sono here means “sleep” as a general state or habit (really “my sleep”, but we don’t need meu).

Portuguese uses the definite article much more than English with general or abstract nouns, so melhorar o sono is the normal way to say “improve sleep”.

Is the word order fixed, or could I move para melhorar o sono earlier in the sentence?

The most natural order is:

Hoje decidi pôr um limite claro ao tempo de ecrã para melhorar o sono.

Here, para melhorar o sono (purpose) comes at the end, which is very common.

You can move it for emphasis, but you need to keep things clear:

Hoje decidi, para melhorar o sono, pôr um limite claro ao tempo de ecrã.
– Sounds more formal / written, with emphasis on the purpose.

Your suggested type of order, like:

Hoje decidi pôr um limite claro para melhorar o sono ao tempo de ecrã

is not good, because para melhorar o sono ends up looking like it modifies limite in a strange way, and ao tempo de ecrã gets “pushed away” from limite, which it belongs to.

So, best is to keep:

um limite claro ao tempo de ecrã (noun + complement) together,
then para melhorar o sono at the end as the purpose.

How do I pronounce the most difficult words here, especially pôr, ecrã, and melhorar?

Approximate European Portuguese pronunciations (using English-like hints):

pôr – like English “poor” but shorter and with lips more rounded; single syllable.
ecrã – eh-KRAHN
- e like “e” in “get”
- cr like “kr” in “crab”
- final ã is nasal: let air go through the nose, no clear final “n”.
melhorar – roughly mel-yo-RAHR
- lh sounds like the “lli” in “million” said quickly: me-LHOrar.
- Stress is on the last syllable: me-lho-RAR.
sono – SOH-noo, first syllable stressed, both o’s are closed (like in “so”).

Spoken smoothly, the sentence is something like: HOH-zh de-see-DEE POOR oong lee-MEE-tuh KLAH-roo ow TEHN-poo d’eh-KRAHN pah-ra mel-yo-RAHR oo SOH-noo.

Why is the verb decidi in the past tense? Could I use another tense like tenho decidido?

Decidi is the pretérito perfeito (simple past), and it’s exactly what you need for “Today I decided…”:

Hoje decidi = Today I decided (completed action at a specific moment).

Tenho decidido is the present perfect and is used differently in Portuguese than in English:

Tenho decidido suggests something like “I have been deciding (repeatedly / habitually)”, and it sounds strange here.

You could also use resolvi (from resolver) with a similar meaning:

Hoje resolvi pôr um limite claro ao tempo de ecrã…
– “Today I resolved/decided to set a clear limit on screen time…”

But Hoje decidi pôr… is the most straightforward equivalent to English “Today I decided to put…”.

Is the whole sentence natural in European Portuguese, or would a native say it differently?

The sentence is natural, correct, and idiomatic in European Portuguese, in a neutral / slightly formal tone:

Hoje decidi pôr um limite claro ao tempo de ecrã para melhorar o sono.

Some equally natural variations a native might also use:

Hoje decidi limitar o tempo de ecrã para dormir melhor.
Hoje decidi reduzir o tempo de ecrã para melhorar o sono.
Hoje decidi pôr um limite ao meu tempo de ecrã para dormir melhor.

Your original version is perfectly good Portuguese, especially in writing or in a careful, thoughtful spoken style.