אני מתעוררת מוקדם, אבל היום השעון לא עבד.

Because Hebrew present-tense verb forms agree with gender and number.
מתעוררת is feminine singular, so it suggests the speaker is female.

A male speaker would say:

אני מתעורר מוקדם, אבל היום השעון לא עבד.

It comes from the dictionary form להתעורר, which means to wake up or to awaken.

So:

• להתעורר = to wake up
• מתעוררת = waking up / wake up (feminine singular present form)

This verb is in the התפעל pattern, which often has a reflexive or change-of-state feel.

It can technically mean either, because Hebrew present tense often covers both simple present and present progressive.

But in this sentence, the natural reading is habitual:

I wake up early

That is because מוקדם and the contrast with היום make it sound like a usual habit versus what happened today.

Here מוקדם is being used like an adverb, meaning early, not like an adjective describing a noun.

Hebrew often uses the masculine singular form of an adjective when it functions adverbially.

So:

• אני מתעוררת מוקדם = I wake up early
• שעה מוקדמת = an early hour

In the second example, מוקדמת is feminine because it describes the feminine noun שעה.

Yes, sometimes you can omit it if the subject is already clear from context:

מתעוררת מוקדם, אבל היום השעון לא עבד.

But there is an important point: in the present tense, Hebrew usually shows gender and number, but not clearly person. So מתעוררת could mean I wake up or she wakes up, depending on context.

Because of that, speakers often keep אני for clarity.

היום is the normal Hebrew word for today. Even though it looks like the day, it is also used as a fixed time expression meaning today.

In this sentence:

אבל היום השעון לא עבד = but today the clock/alarm clock didn’t work

Placing היום right after אבל highlights the contrast:

• usually: אני מתעוררת מוקדם
• but today: השעון לא עבד

Hebrew word order is fairly flexible, so you could also say:

אבל השעון לא עבד היום

That is also natural, with a slightly different focus.

Literally, השעון means the clock or the watch.

In this context, because the sentence is about waking up early, it most likely means the alarm clock.

The ה־ at the beginning is the definite article, meaning the.

So:

• שעון = clock / watch
• השעון = the clock / the watch

לא is the standard Hebrew word for not. It is placed before the verb it negates.

So:

• עבד = worked
• לא עבד = did not work

This is the normal way to negate verbs in Hebrew in past, present, and future.

עבד is the past tense, third person masculine singular form of לעבוד (to work).

It matches the subject השעון, which is masculine singular.

So the grammar is:

• subject: השעון
• verb: עבד

Also, just like in English, Hebrew uses לעבוד not only for a person working at a job, but also for a machine or device working / functioning.

לא עבד means didn’t work on that specific occasion.
That fits the idea here: today, the clock/alarm failed.

By contrast:

• לא עובד = is not working / doesn’t work
• לא עבד = didn’t work

So:

• השעון לא עובד = the clock isn’t working
• השעון לא עבד = the clock didn’t work

In this sentence, the speaker is talking about what happened today, so the past tense is the natural choice.