Ich höre meinen Atem.

Because Atem is the direct object of the verb hören (to hear), so it has to be in the accusative case.

• Nominative: mein Atem = my breath as the subject
• Accusative: meinen Atem = my breath as the object

So in Ich höre meinen Atem, I am the subject, and my breath is what I hear.

Atem is masculine: der Atem.

That is why the possessive changes like this:

• mein Atem → nominative masculine
• meinen Atem → accusative masculine

If the noun were neuter or feminine, the form would be different.

In German, hören normally takes a direct object in the accusative, just like to hear in English takes an object.

Examples:

• Ich höre Musik.
• Ich höre den Hund.
• Ich höre meinen Atem.

So whenever you hear something, the thing heard is usually in the accusative.

Here, Atem means breath.

So Ich höre meinen Atem means that you can hear the sound of your own breathing/breath.

A small nuance:

• Atem = breath
• Atmung = breathing / respiration as a process

In everyday German, Atem is the natural word in this sentence.

It is capitalized because it is the first word of the sentence, not because German always capitalizes the word for I.

Unlike English, German does not always capitalize ich in the middle of a sentence.

Examples:

• Ich höre meinen Atem.
• Er sagt, dass ich müde bin.

So only the first Ich is capitalized because it starts the sentence.

Because all nouns are capitalized in German.

So:

• ich = pronoun, usually not capitalized unless at the start
• höre = verb, not capitalized
• Atem = noun, so capitalized

This is one of the most important spelling rules in German.

Yes. Mein is a possessive determiner, and it changes its ending depending on gender, case, and number, much like articles do.

For masculine singular:

• nominative: mein
• accusative: meinen

So:

• mein Atem = my breath (subject form)
• meinen Atem = my breath (object form)

You can think of meinen here as the accusative masculine form of mein.

Yes, absolutely. Ich höre meinen eigenen Atem means I hear my own breath and sounds very natural.

Adding eigenen makes the idea of my own more explicit.

Compare:

• Ich höre meinen Atem. = I hear my breath.
• Ich höre meinen eigenen Atem. = I hear my own breath.

Both are correct; the second is just a bit more emphatic.

The sentence follows standard German main-clause word order:

• Ich = subject
• höre = conjugated verb
• meinen Atem = object

So the structure is:

Subject + verb + object

This is the same basic pattern as English:

• I hear my breath.

A simple pronunciation guide is:

ikh HUH-ruh MY-nen AH-tem

A few useful points:

• ich has the soft ch sound, not a hard k
• höre has an ö sound, which does not exist exactly in English
• meinen sounds roughly like MY-nen
• Atem has stress on the first syllable: AH-tem

A more careful approximation is: ikh HUR-uh MY-nen AH-tem

In this meaning, you usually use it in the singular.

• der Atem = breath

German more often expresses repeated breaths with other wording, such as:

• Atemzüge = breaths
• Ich höre seine Atemzüge. = I hear his breaths.

So in Ich höre meinen Atem, the singular is the normal and natural choice.

Yes, that is a very natural English translation of the idea, even though the German sentence literally says I hear my breath.

Depending on context, English may prefer:

• I hear my breath
• I hear myself breathing
• I can hear my breathing

All of these can match Ich höre meinen Atem, depending on style and context.