El baile social usa cambios de pareja.

Because baile is a masculine noun in Spanish, so it takes el.

• el baile = the dance / dancing
• la danza = dance, but this is a different noun

Even though social ends in -al, that does not affect the gender. The gender is determined by baile, not by the adjective.

Baile social is a noun phrase meaning social dancing or social dance.

• baile = dance / dancing
• social = social

In Spanish, this is a very normal way to express the idea. It refers to dancing done in a social setting, often with different partners, rather than performance or competition.

In Spanish, adjectives usually come after the noun.

So:

• baile social = social dance
• literally: dance social

This is one of the most basic word-order differences between English and Spanish.

Usa is the third-person singular form of usar in the present tense.

The subject is el baile social, which is singular, so the verb must also be singular:

• el baile social usa
• not usan

So grammatically, it means social dancing uses...

Yes. In a sentence like this, usa does not have to sound as literal as English uses sometimes does.

Depending on context, it can suggest:

• uses
• makes use of
• involves
• employs

So the Spanish is natural even if the most natural English translation might use a different verb.

Because Spanish often leaves out the article when speaking about something in a general sense.

So:

• usa cambios de pareja = it uses partner changes / it involves partner changes in general

If you said:

• usa los cambios de pareja

that would sound more like you are referring to specific partner changes already known in the conversation.

Literally, it is:

• cambios = changes
• de pareja = of partner / of partner-switching / involving partners

A very natural interpretation is partner changes or changing partners.

In dance contexts, cambio de pareja is a normal way to talk about rotating or switching partners.

Spanish often uses the singular after de when it describes a type, category, or general concept.

So cambios de pareja means something like:

• changes of partner
• partner changes
• partner-switching

It does not necessarily mean there is only one partner. The singular here is idiomatic and refers to the concept in general.

Here, pareja means partner.

This word can mean different things depending on context:

• mi pareja = my partner / my boyfriend / my girlfriend
• una pareja = a couple
• in dancing, pareja often means dance partner

In this sentence, the dance context makes partner the correct interpretation.

Yes, but the original order is the most neutral.

For example, you could say:

• El baile social utiliza cambios de pareja.

This is very similar, just slightly more formal because utiliza is a bit more formal than usa.

You could also move things around for emphasis in some contexts, but El baile social usa cambios de pareja is the straightforward standard order:

subject + verb + object

Usa is perfectly understandable and grammatically correct. But depending on context, Spanish speakers might also say:

• incluye cambios de pareja = includes partner changes
• implica cambios de pareja = involves partner changes
• se basa en cambios de pareja = is based on partner changes

So usar works, but there are other verbs that may sound more natural in certain explanations.

Because the idea is that partner-changing happens repeatedly, not just once.

• cambio de pareja = a partner change
• cambios de pareja = partner changes

The plural fits the idea of a dance setting where people switch partners multiple times.

A simple pronunciation guide is:

el BAI-le so-THYAL OO-sa KAM-byos de pa-RE-ha

In most of Spain:

• c before i in social sounds like th in think
• j in pareja sounds like a strong throaty h
• ll in baile is pronounced like a regular y sound in most modern accents

That said, pronunciation varies across the Spanish-speaking world, and Latin American pronunciation would sound slightly different.