Das Handy empfängt eine Nachricht.

Because Handy is a neuter noun in German. German nouns have grammatical gender, so you have to learn the noun together with its article:

• das Handy = the mobile phone / cell phone

In this sentence, das Handy is the subject, so it is in the nominative case.

Yes. In everyday German, das Handy means mobile phone or cell phone.

This is a good example of a false friend: in English, handy is usually an adjective meaning useful or convenient, but in German Handy is a noun.

Because empfangen is the infinitive form, and here the verb has to be conjugated to match the subject.

The subject is das Handy, which is third person singular (it), so the verb becomes:

• ich empfange
• du empfängst
• er/sie/es empfängt

So Das Handy empfängt ... means The phone receives ...

This verb has a stem-vowel change in the present tense for du and er/sie/es forms.

So:

• ich empfange
• du empfängst
• er/sie/es empfängt

This is similar to other strong verbs in German that change their vowel in some present-tense forms.

It is in the accusative case, because it is the direct object of the verb empfängt.

The phone is doing the action, and the message is what is being received.

So:

• das Handy = subject, nominative
• eine Nachricht = direct object, accusative

Because Nachricht is a feminine noun: die Nachricht.

The indefinite article for feminine singular is:

• nominative: eine
• accusative: eine

So even though Nachricht is in the accusative here, the article still stays eine.

Compare:

• ein Mann → einen Mann masculine changes
• eine Nachricht → eine Nachricht feminine does not change here

This sentence uses the very common German main-clause pattern:

• Subject + finite verb + object

So:

• Das Handy = subject
• empfängt = finite verb
• eine Nachricht = object

A useful rule is that in a normal German main clause, the finite verb goes in second position.

Because all German nouns are capitalized.

So in this sentence:

• Handy is a noun
• Nachricht is a noun

That is why both begin with capital letters.

Not necessarily. Nachricht can mean message in a general sense, and depending on context it could refer to:

• a text message
• a message in an app
• a notification
• a general incoming message

So the exact type of message depends on context.

You might hear something similar in casual speech, but empfängt is the more natural verb when a device is the thing receiving a signal or message.

• empfangen often sounds more technical or device-related
• bekommen is more like to get

For a person, bekommen is very common:

• Ich bekomme eine Nachricht.

For a phone or device, empfängt fits especially well.