Я почти не слышу тебя из-за слабого сигнала.

In Russian, не слышу literally means I do not hear. With почти (almost), the phrase почти не слышу means I almost don’t hear / I can barely hear.

This is a very natural Russian way to express weak perception:

• Я почти не вижу. — I can hardly see.
• Я почти не понимаю. — I barely understand.

So почти не слышу тебя is a normal way to say I can barely hear you.

Because почти modifies the whole negative idea: almost not hearing.

• Я почти не слышу тебя. — I can barely hear you.

This word order is the most natural. Russian often puts adverbs like почти before the verb phrase they modify.

If you moved it around, the sentence might sound less natural or shift emphasis. The standard version is:

• Я почти не слышу тебя.

Слышу is the 1st person singular present tense of слышать (to hear).

So:

• я слышу — I hear
• ты слышишь — you hear
• он/она слышит — he/she hears
• мы слышим — we hear
• вы слышите — you hear
• они слышат — they hear

In this sentence, я is the subject, so the verb must be слышу:
Я почти не слышу... — I can barely hear...

Because ты is the subject form (you), while тебя is the object form.

Here, you is the person being heard, so Russian uses the object form:

• ты — you (subject)
• тебя — you (object)

Compare:

• Ты слышишь меня? — Do you hear me?
• Я слышу тебя. — I hear you.

After слышу, the person heard is normally in the accusative case, so тебя is correct.

Good question. Russian sometimes uses the genitive with negation, but with direct objects referring to specific people, the accusative is very common and natural.

So:

• Я не вижу тебя. — I don’t see you.
• Я не слышу тебя. — I don’t hear you.

Using тебя here is standard.

You may learn that older or more formal Russian can sometimes use genitive after negation in some contexts, especially with non-specific things, but for a sentence like this, не слышу тебя is exactly what learners should expect.

Из-за is a preposition meaning because of, due to, or sometimes from behind depending on context.

Here it means because of:

• из-за слабого сигнала — because of the weak signal

It is always written with a hyphen: из-за.

This preposition requires the genitive case, which is why the next words change form.

It is the genitive case, because из-за requires genitive.

Base forms:

• слабый сигнал — a weak signal

After из-за, they become:

• из-за слабого сигнала — because of a weak signal

Changes:

• слабый → слабого
• сигнал → сигнала

So the grammar is:

• из-за
  • genitive

Other examples:

• из-за дождя — because of the rain
• из-за шума — because of the noise
• из-за плохой связи — because of the bad connection

Yes, but the meaning is a little different.

• Я плохо слышу тебя. — I hear you poorly / I’m having trouble hearing you.
• Я почти не слышу тебя. — I can barely hear you.

So плохо слышу suggests difficulty, while почти не слышу is stronger: the sound is so weak that you can hardly hear at all.

Russian often does not need a separate word for can when talking about perception.

English says:

• I can hear you
• I can’t hear you well
• I can barely hear you

Russian usually just uses the verb itself:

• Я слышу тебя. — I hear / I can hear you.
• Я плохо слышу тебя. — I don’t hear you well.
• Я почти не слышу тебя. — I can barely hear you.

So the idea of ability is often understood from context.

Russian word order is more flexible than English, but the neutral order here is:

• Я почти не слышу тебя из-за слабого сигнала.

You could rearrange parts for emphasis, for example:

• Из-за слабого сигнала я почти не слышу тебя.
  This emphasizes the reason first: Because of the weak signal...

• Тебя я почти не слышу из-за слабого сигнала.
  This puts extra focus on you.

But for everyday neutral speech, the original order is the most natural.

Yes. In this context, сигнал usually means a communication signal, such as phone signal, mobile reception, or connection quality.

So из-за слабого сигнала naturally means:

• because the phone signal is weak
• because the connection is weak
• because reception is bad

In real conversation, Russians might also say:

• из-за плохой связи — because of the bad connection
• у меня слабый сигнал — I have a weak signal

All of these are common in calls or voice chats.