El supervisor capacita personal nuevo.

In Spanish, personal can be a noun meaning staff, personnel, employees. That is what it is in this sentence.

So here:

• personal = staff/personnel
• not the English adjective personal

This is a very common business/workplace use in Latin America. For example:

• contratar personal = to hire staff
• capacitar personal = to train staff

Capacita is the third-person singular present tense form of capacitar.

The subject is El supervisor, which is singular, so the verb must also be singular:

• el supervisor capacita = the supervisor trains

Compare:

• El supervisor capacita... = The supervisor trains...
• Los supervisores capacitan... = The supervisors train...
• capacitar = to train (the infinitive, not a complete conjugated verb)

Because personal is a collective noun. Grammatically, it is singular, even though it refers to a group of people.

That is similar to English staff or personnel.

So Spanish treats it as singular here:

• personal nuevo = new staff / new personnel

That is why the adjective is also singular:

• nuevo, not nuevos

In Spanish, adjectives usually come after the noun.

So the normal order is:

• personal nuevo = new staff
• empleado nuevo = new employee

Putting nuevo before the noun is much less neutral and can change the nuance. For this sentence, personal nuevo is the standard and natural wording.

Great question. In workplace or administrative Spanish, especially in concise styles, Spanish can omit the article with nouns like personal when speaking in a general sense:

• capacita personal nuevo = trains new staff

This can sound like describing a job function or general activity.

But El supervisor capacita al personal nuevo is also very natural, and many speakers would prefer it in everyday full-sentence Spanish when referring to a specific group of newly hired staff.

So the difference is roughly:

• capacita personal nuevo = more general, concise, sometimes business-style
• capacita al personal nuevo = more explicit, often more natural in ordinary speech when the group is specific

The personal a is often used before direct objects that are specific people:

• Veo a María
• Conozco a los empleados

But with personal meaning staff/personnel, Spanish often treats it more like a collective or institutional noun, especially in general statements. Because of that, the a may be omitted.

So in this sentence, no a is possible and natural in this general/business-style wording:

• El supervisor capacita personal nuevo

If the speaker is thinking of a specific set of employees, many speakers would say:

• El supervisor capacita al personal nuevo

That uses both the article and the contraction al.

Because it agrees with personal, which is grammatically a masculine singular noun.

So:

• personal nuevo = correct
• personal nuevos = not correct here
• personal nueva = not correct here

Even though the staff may include men and women, grammatical agreement is based on the noun personal, not on the actual number or gender of the people in the group.

Spanish often drops subject pronouns, but here El supervisor is a full noun phrase, not just a pronoun. It is included to tell you exactly who does the action.

If the context already made the subject clear, Spanish could use a shorter sentence, but then the meaning might be less clear on its own:

• Capacita personal nuevo

By itself, that could sound incomplete, context-dependent, or even ambiguous in some situations. Including El supervisor makes the sentence clear and straightforward:

• El supervisor capacita personal nuevo

They are similar, but not always identical.

• capacitar often means to train, to prepare, or to qualify someone for a job or task
• entrenar often means to train in the sense of practice, coaching, or drilling, and it is also very common in sports

In workplace Spanish, especially in Latin America, capacitar is extremely common for employee training. So in this sentence, capacita is a very natural verb choice.