Aprender un nuevo idioma vale la pena.

Because aprender is an infinitive, and in Spanish an infinitive can work like a noun in English.

So Aprender un nuevo idioma functions as the subject of the sentence, similar to Learning a new language in English.

• Aprender = to learn
• Aprender un nuevo idioma = learning a new language

This is very common in Spanish:

• Fumar es malo. = Smoking is bad.
• Viajar abre la mente. = Traveling opens the mind.

Spanish often uses the infinitive by itself as a general idea, without el.

So:

• Aprender un nuevo idioma vale la pena. = Learning a new language is worth it.

You may sometimes see el aprender, but that sounds more formal, abstract, or stylistically marked. In normal everyday Spanish, using just aprender is the natural choice here.

Vale la pena is a very common expression meaning it is worth it or it is worthwhile.

Literally:

• vale = is worth
• la pena = the trouble, effort, or pain

So the phrase suggests something is worth the effort involved.

Other examples:

• Vale la pena estudiar. = It’s worth studying.
• No vale la pena discutir. = It’s not worth arguing.

Even though pena can mean sadness or pity in other contexts, in this fixed expression it refers more to trouble/effort.

Because the subject is the whole action Aprender un nuevo idioma, and that whole idea is treated as singular.

So Spanish uses singular vale:

• Aprender un nuevo idioma vale la pena.

Think of it like English:

• Learning a new language is worth it.

Not:

• Learning a new language are worth it.

Because un is the form used before a masculine singular noun.

• un idioma = a language

Uno is used when the number stands alone, not directly before a noun:

• Tengo un libro. = I have a book.
• Tengo uno. = I have one.

So before idioma, you need un, not uno.

Because not all Spanish nouns ending in -a are feminine.

Idioma is masculine:

• el idioma
• un idioma
• un nuevo idioma

This happens with several words of Greek origin ending in -ma:

• el problema
• el sistema
• el programa
• el tema

So this is a pattern worth remembering.

In Spanish, adjectives can sometimes go before or after the noun, and the position can affect nuance.

• un nuevo idioma usually means a new language in the general sense: a language that is new to you, another language, an additional one.
• un idioma nuevo is also possible, and often sounds a bit more literal or contrastive, as if emphasizing that the language itself is new or newly introduced.

In many everyday contexts, both are acceptable, but un nuevo idioma is very natural here.

Yes, absolutely. That sentence is also correct and natural.

The difference is mostly one of nuance:

• un nuevo idioma = a new language, another language, one that is new to you
• un idioma nuevo = a new language, with a slightly stronger focus on new as a descriptive quality

In everyday use, both versions can work.

Yes. Valer la pena is very common and natural across Latin America.

You may also hear merece la pena, especially in Spain:

• Aprender un nuevo idioma merece la pena.

That version is also correct and understood in Latin America, but vale la pena is generally the more common everyday choice there.

It comes from the verb valer, which means to be worth.

Here is the relevant form:

• vale = it is worth / is worth

Examples:

• Vale mucho. = It is worth a lot.
• No vale nada. = It is worth nothing.
• Vale la pena intentarlo. = It’s worth trying.

So in your sentence, vale is the third-person singular present form of valer.

Yes, it is completely natural and idiomatic.

Aprender un nuevo idioma vale la pena sounds like normal, fluent Spanish and would be understood throughout Latin America.

It is a good model sentence because it uses:

• an infinitive as the subject
• a very common expression: vale la pena
• normal adjective agreement: nuevo idioma

A simple pronunciation guide would be:

ah-pren-DER oon NWEH-bo ee-DYOH-mah BAH-leh lah PEH-nah

A few helpful points:

• aprender stress is on the last syllable: -der
• nuevo begins with a nw sound: NWEH-bo
• idioma is stressed on dio: ee-DYOH-ma
• vale sounds like BAH-leh in most of Latin America, since v and b are pronounced very similarly in Spanish
• pena has a regular peh-na sound

Because valer la pena is a fixed expression. The article la is part of the phrase.

So you learn it as a chunk:

• valer la pena = to be worth it

You normally do not remove la:

• correct: Vale la pena
• not natural: Vale pena

This is one of those expressions that is best memorized as a whole unit.