El remitente alemán firma el aviso.

No. Remitente is a common-gender noun, which means the noun form stays the same for both males and females, and the article shows the gender:

• el remitente = the male sender
• la remitente = the female sender

In this sentence, it is masculine because both el and alemán are masculine.

In Spanish, adjectives of nationality usually come after the noun:

• el remitente alemán = the German sender
• la empresa mexicana = the Mexican company

This is the normal word order in Spanish. Putting alemán before the noun would sound unusual here.

The accent mark shows where the stress goes: a-le-MÁN.

Without the accent, Spanish spelling rules would suggest a different stress pattern. The written accent tells you the last syllable is stressed.

It also helps distinguish the correct form of the adjective:

• alemán = masculine singular
• alemana = feminine singular
• alemanes = masculine plural
• alemanas = feminine plural

Firmar is the infinitive, meaning to sign.
Firma is the present tense, third-person singular form:

• yo firmo = I sign
• tú firmas = you sign
• él / ella / usted firma = he / she / you sign

Since the subject is el remitente alemán, which is third-person singular, the correct verb form is firma.

The subject is el remitente alemán. That is the person performing the action.

A simple breakdown is:

• El remitente alemán = subject
• firma = verb
• el aviso = direct object

So the sentence structure is:

Subject + Verb + Object

This is very similar to standard English word order.

Spanish often uses the definite article more regularly than English does.

Here, both nouns are presented as specific:

• el remitente alemán = the German sender
• el aviso = the notice / the warning / the announcement

So el appears before both nouns because both are masculine singular and definite.

Because el aviso is an inanimate direct object.

Spanish uses the personal a mainly before specific people (and sometimes pets). For example:

• Veo al profesor = I see the teacher
• Veo el aviso = I see the notice

Since aviso is not a person, there is no a.

Yes, that is grammatically possible, but it is less neutral.

The most standard, straightforward order is:

• El remitente alemán firma el aviso.

If you say:

• Firma el aviso el remitente alemán.

it can sound more literary, emphatic, or like you are clarifying who signs it. In normal learner Spanish, the original word order is the best choice.

Yes. Spanish often omits subject pronouns and even full subjects when the context is clear.

For example, if everyone already knows who the sender is, you might simply say:

• Firma el aviso. = He/She signs the notice.

But if you want to specify exactly who does the action, you keep the full subject:

• El remitente alemán firma el aviso.

A Latin American pronunciation would be approximately:

• remitente = reh-mee-TEN-teh
• alemán = ah-leh-MAHN
• firma = FEER-mah
• aviso = ah-BEE-soh

A few helpful notes:

• The r in remitente is a light tap.
• The i in firma sounds like ee.
• In most of Latin America, b and v sound very similar, so aviso begins with a soft b/v sound.

Not always. Aviso can mean things like:

• notice
• warning
• announcement
• ad
• message

The exact meaning depends on context. In this sentence, you would choose the English meaning that best matches the situation already given to the learner.

Yes. Firma can be:

• a verb form: he/she signs
• a noun: signature

In this sentence, it is clearly the verb because it comes between the subject and the object:

• El remitente alemán firma el aviso.

If it were a noun, the sentence structure would be different.

You would change the article and the nationality adjective:

• La remitente alemana firma el aviso.

Notice:

• el → la
• alemán → alemana

The noun remitente itself does not change.