בבית אני מחברת רמקול קטן לטלפון כשאני רוצה לשמוע מוזיקה עם חברים.

Because of מחברת. This is the feminine singular present form of לחבר = to connect.

• אני מחברת = a female speaker says I connect / I’m connecting
• A male speaker would say אני מחבר

Also, רוצה is one of those forms that is spelled the same for masculine and feminine in unpointed Hebrew, but pronounced differently:

• masculine: rotze
• feminine: rotza

So מחברת is what clearly tells you the speaker is female.

Not in this sentence. Here it is a verb: I connect / I’m connecting.

Hebrew מחברת can also be the noun notebook, but context makes the difference clear:

• אני מחברת רמקול קטן לטלפון must be verbal, because it comes after אני and is followed by what is being connected
• the noun מחברת would fit in a sentence like יש לי מחברת = I have a notebook

So this is a very common case where the same spelling can represent different words.

Here בבית means at home.

Literally, it is ב־ + בית:

• ב־ = in / at
• בית = house / home

In Hebrew, at home is often expressed with בבית, literally in the house/home.

Also, in normal unpointed spelling, בבית can represent more than one pronunciation:

• babayit = in the house / at home
• bebayit = in a house

Context tells you which one is meant. Here it clearly means at home.

Because כשאני רוצה is a full clause meaning when I want.

The first אני belongs to the main clause:

• בבית אני מחברת... = At home I connect...

The second אני belongs to the when clause:

• כשאני רוצה... = when I want...

This is normal Hebrew. Just like in English, each clause can have its own subject.

כש means when here.

It is a shorter everyday form related to כאשר, which is a more formal word for when.

So:

• כשאני רוצה = when I want
• more formally: כאשר אני רוצה

In everyday speech and writing, כש is extremely common.

Because in Hebrew, adjectives normally come after the noun.

So:

• רמקול קטן = a small speaker
• טלפון קטן = a small phone

The adjective also has to agree with the noun in gender and number. Since רמקול is masculine singular, the adjective is also masculine singular: קטן.

If the noun were feminine, the adjective would change too:

• קופסה קטנה = a small box

Because the verb לחבר normally uses the pattern:

לחבר X ל־Y = to connect X to Y

So here:

• מחברת רמקול קטן לטלפון
• literally: I connect a small speaker to the phone

That ל־ is the normal preposition after this verb.

One extra thing: in unpointed Hebrew, לטלפון can be read either as:

• letelefon = to a phone
• latelefon = to the phone

The spelling is the same, so context decides.

Because after רוצה = want, Hebrew normally uses an infinitive.

So:

• רוצה לשמוע = want to hear / want to listen
• literally: want to-hear

This works very much like English want to + verb.

Examples:

• אני רוצה לאכול = I want to eat
• אני רוצה ללכת = I want to go
• אני רוצה לשמוע מוזיקה = I want to listen to music

Yes, literally לשמוע is to hear, but in Hebrew it is also very commonly used where English says listen to, especially with music.

So:

• לשמוע מוזיקה = to listen to music

Hebrew also has להאזין ל־, which is closer to to listen to in a more deliberate or formal sense:

• להאזין למוזיקה

But in everyday speech, לשמוע מוזיקה is extremely natural.

Because חברים is the masculine plural, and in Hebrew that can be used for:

• a group of male friends
• a mixed group of friends
• an unspecified group

חברות would specifically mean female friends.

So if the speaker is listening to music with male or mixed friends, עם חברים is the normal choice.

It can mean either one.

Hebrew present tense often covers both the simple present and the progressive meaning:

• אני מחברת can mean I connect
• or I am connecting

Context tells you which is more natural.

In this sentence, because of כשאני רוצה = when I want, it sounds more like a habitual action:

At home, I connect a small speaker to the phone when I want to listen to music with friends.

Hebrew word order is fairly flexible, and starting with בבית puts the setting first:

At home, I...

That is very natural.

You could also say something like:

אני מחברת רמקול קטן לטלפון בבית כשאני רוצה לשמוע מוזיקה עם חברים

but the original version highlights where this usually happens. Starting with a place expression like בבית is common in Hebrew.