אני מודאג, כי הוא עוד לא ענה לי.

No. מודאג is an adjective, not a verb. The sentence literally works like:

אני מודאג = I am worried

In Hebrew, the present tense of to be is usually not stated, so there is no separate word for am here. Hebrew simply says:

• אני מודאג = I am worried
• literally: I worried/worried-state

So this is a very normal Hebrew pattern: subject + adjective.

Yes. מודאג is the masculine singular form.

If the speaker is female, you would say:

• אני מודאגת = I am worried

Other forms are:

• מודאג = masculine singular
• מודאגת = feminine singular
• מודאגים = masculine plural / mixed plural
• מודאגות = feminine plural

So the form of מודאג agrees with the person who is worried, not with הוא later in the sentence.

Yes. כי is a very common word meaning because.

So:

• אני מודאג, כי... = I’m worried because...

It is one of the most standard ways to connect two clauses in Hebrew.

עוד לא means not yet.

So:

• הוא עוד לא ענה לי = He hasn’t answered me yet

Literally, עוד often means still / more / yet, and together with לא it gives the idea of something that has not happened up to this point.

A very close alternative is עדיין לא, which also means not yet / still not.

So these are both possible:

• הוא עוד לא ענה לי
• הוא עדיין לא ענה לי

Both are natural.

Because the Hebrew verb ענה in the sense of answer normally takes an indirect object with ל־.

So Hebrew says:

• הוא ענה לי
• literally: he answered to me
• natural English: he answered me

This is very important, because English says answer someone, but Hebrew usually says answer to someone with ל.

More examples:

• עניתי לו = I answered him
• היא לא ענתה לנו = She didn’t answer us

So לי here means to me.

ענה is the past tense, third person masculine singular:

• ענה = he answered

In this sentence, Hebrew uses past tense together with עוד לא to express what English often says with the present perfect:

• הוא עוד לא ענה לי
  = He hasn’t answered me yet

That is very normal in Hebrew. English uses hasn’t answered, but Hebrew often uses a past form in this kind of context.

Hebrew often can leave subject pronouns out, because the verb form already gives some information. But in the past tense, some forms can be less clear on their own, and using the pronoun often sounds natural.

So:

• הוא עוד לא ענה לי = very natural
• עוד לא ענה לי = also possible in the right context

Including הוא makes the subject explicit: he.

Likewise, אני is often included for clarity or emphasis, though in some cases Hebrew can omit pronouns more easily than English.

The given word order is very natural:

• אני מודאג, כי הוא עוד לא ענה לי.

But Hebrew word order is somewhat flexible, especially for emphasis.

For example, you might also hear:

• כי הוא עוד לא ענה לי, אני מודאג.

That changes the focus slightly, but the basic meaning stays the same.

Still, for a learner, the original order is the safest and most standard.

A simple learner-friendly pronunciation would be:

• אני = a-NEE
• מודאג = mu-DAG
• כי = kee
• הוא = hoo
• עוד = od
• לא = lo
• ענה = a-NA
• לי = lee

A rough full pronunciation:

a-NEE mu-DAG, kee hoo od lo a-NA lee

A small note: the letter ע in modern Hebrew is often very weak in everyday speech, so learners usually do not need to make a strong special sound for it at first.

Both can be possible, but they are not exactly the same in feel.

• אני מודאג = I am worried / concerned
• אני דואג = I worry / I’m worrying / I’m concerned

מודאג is an adjective describing a state: worried.
דואג is a participle/present-tense form from the verb לדאוג, and it can sound a little more verbal or ongoing.

In many situations, both are natural, but אני מודאג is a very straightforward way to say I’m worried.

You would change the parts that agree with gender.

If the speaker is female:

• אני מודאגת, כי הוא עוד לא ענה לי.

If the person who has not answered is female:

• אני מודאג, כי היא עוד לא ענתה לי.

If both are female:

• אני מודאגת, כי היא עוד לא ענתה לי.

So:

• מודאג / מודאגת agrees with אני
• ענה / ענתה agrees with הוא / היא