Prietenii glumesc la prânz.

Because prietenii means the friends, while prieteni just means friends.

In Romanian, the definite article is usually attached to the end of the noun instead of being a separate word like English the.

• prieten = friend
• prieteni = friends
• prietenii = the friends

The two is come from:

• one i belonging to the plural form prieteni
• one i belonging to the definite article

So prietenii glumesc means the friends are joking / the friends joke.

That is a normal feature of Romanian grammar. Unlike English, Romanian usually puts the at the end of the noun.

For example:

• băiat = boy

• băiatul = the boy

• fată = girl

• fata = the girl

• prieteni = friends
• prietenii = the friends

So in this sentence, prietenii already includes the idea of the.

Glumesc is the present tense of the verb a glumi, meaning to joke.

Here it is third person plural, agreeing with prietenii:

• ei/ele glumesc = they joke / they are joking

So:

• Prietenii glumesc = The friends joke or The friends are joking

One thing to notice: glumesc can also mean I joke with the pronoun eu, because some Romanian verb forms are identical in different persons. The subject tells you which meaning is intended.

Because Romanian often uses the simple present where English can use either:

• they joke
• they are joking

So glumesc can cover both ideas, depending on context.

Romanian does have ways to emphasize ongoing action, but in everyday sentences the simple present is very common and natural.

La prânz means at noon, at lunchtime, or around lunch.

The preposition la is very commonly used in Romanian with times and occasions.

So:

• la prânz = at noon / at lunch
• la două = at two
• la noapte = tonight / at night

In this sentence, la prânz tells you when the action happens.

It can mean both, depending on context.

• prânz can refer to the middle of the day: noon
• it can also refer to the meal eaten then: lunch

So la prânz is often understood as at lunchtime or around noon. English may choose one wording or the other depending on context, but Romanian uses the same word.

Yes. Romanian word order is more flexible than English word order.

The neutral, most straightforward order here is:

• Prietenii glumesc la prânz.

But other orders are possible for emphasis, for example:

• La prânz, prietenii glumesc. = At lunchtime, the friends joke.
• Glumesc prietenii la prânz. = possible, but less neutral and more marked

For learners, the original order is the safest and most natural one to use first.

Because the subject is explicitly given: prietenii.

Romanian verbs often make the subject clear by their endings, so subject pronouns are often omitted. But when a noun is present, that noun tells you who is doing the action.

So here:

• prietenii = the friends
• therefore glumesc must mean they joke / they are joking

If the sentence were just Glumesc, then context would be needed, because that form can mean I joke or they joke.

It is pronounced roughly like prie-te-nii, with the stress on te.

A simple learner-friendly approximation is:

• prie-te-NII

The ending -ii does not sound exactly like English spelling might suggest. It is usually pronounced as a long ee sound or an ee plus a very slight y glide, depending on speech.

So prietenii is not pronounced like two fully separate English i sounds.

Prânz is pronounced roughly like prɨnz.

The tricky part is â, a specifically Romanian vowel. It is not the same as English a, i, or u. It is a central sound made with the tongue high in the mouth.

A practical approximation for beginners is:

• something like a tight, central uh sound

Also:

• prânz is basically one syllable
• the final z is pronounced

So la prânz is approximately:

• la prɨnz

Yes, but it would not mean exactly the same thing.

• Prietenii glumesc la prânz = The friends joke at lunch
• Prieteni glumesc la prânz = Friends joke at lunch or Some friends joke at lunch

Without the article, the noun is indefinite or more general. With prietenii, you are talking about specific friends already known in the context.

So if the intended meaning is the friends, you need prietenii.