El molde auricular sujeta el auxiliar auditivo.

Molde auricular means an earmold: the custom-shaped piece that fits in or around the ear and helps position or attach a hearing device properly.

• molde = mold, shaped piece
• auricular = related to the ear

In this medical/device context, it does not mean a mold growing in the ear. It means a molded ear piece.

In Spanish, most descriptive and classifying adjectives usually come after the noun.

So:

• molde auricular = ear mold / earmold
• literally: mold auricular

This is very normal Spanish word order. In English, we usually put the modifier first, but Spanish often puts it after the noun.

Sujeta comes from the verb sujetar, which means:

• to hold
• to secure
• to keep in place
• to fasten

Here, sujeta is third-person singular, present tense:

• (él/ella/usted) sujeta = it holds / it secures

So in this sentence, it means the earmold holds or keeps in place the hearing aid.

Because sujetar is the infinitive form, like to hold.

The sentence needs a conjugated verb, because it is saying what the subject does:

• El molde auricular sujeta... = The earmold holds...

If you used sujetar, it would not form a complete normal statement here.

In this sentence, the most natural reading is:

• El molde auricular = subject
• sujeta = verb
• el auxiliar auditivo = direct object

So:

• The earmold holds the hearing aid

Spanish often follows subject + verb + object, just like English.

Also, the meaning of the words helps: logically, the earmold is the part that secures the hearing aid in place.

Because both molde auricular and auxiliar auditivo are masculine singular noun phrases, so they take el.

• el molde auricular
• el auxiliar auditivo

Spanish uses articles very often, sometimes more often than English does. In technical or descriptive sentences like this one, using the definite article sounds natural.

Usually, yes, they refer to a hearing aid.

But there is a difference in tone and usage:

• auxiliar auditivo = more formal, technical, or medical
• audífono = more common in everyday speech

A useful note for Latin America: in some places, audífonos can also mean headphones, so auxiliar auditivo can be clearer in medical contexts.

Here, auxiliar functions as the main noun in the phrase auxiliar auditivo, and auditivo describes it.

So the structure is basically:

• auxiliar = aid / helper
• auditivo = auditory / hearing-related

Together, auxiliar auditivo means hearing aid.

In real usage, it is best learned as a fixed expression.

Because the personal a is mainly used with people (and sometimes pets or personified beings), not ordinary things.

Compare:

• Veo a María. = I see María.
• Veo el auxiliar auditivo. = I see the hearing aid.

Since el auxiliar auditivo is a thing, not a person, there is no a.

Yes, in many contexts you could, but the nuance is slightly different.

• sujeta = secures, fastens, keeps in place
• sostiene = supports, holds up

For a device part whose job is to keep something fixed or attached, sujeta is often more precise.

Another possible verb in some contexts is:

• mantiene en su lugar = keeps in place

A simple pronunciation guide:

• sujeta ≈ soo-HEH-tah

Important point:

• The j in Spanish is a strong throaty sound, not the English j in job.

So it is soo-HEH-tah, not soo-JEH-tah.

Not very naturally.

A very literal version would be:

• The auricular mold secures the auditory aid

That is understandable, but not natural English.

A more natural English translation would usually be something like:

• The earmold holds the hearing aid in place.

So when learning Spanish, it helps to understand the literal parts, but also to learn the natural device vocabulary in both languages.