Ben gece çay içmiyorum, çünkü sonra uyuyamıyorum.

Ben is not strictly necessary.

Turkish verbs already show the subject:

• içmiyorum = I am not drinking / I don’t drink
• uyuyamıyorum = I can’t sleep

So the sentence could naturally be:

Gece çay içmiyorum, çünkü sonra uyuyamıyorum.

Adding Ben can:

• give a little emphasis to I
• make the sentence clearer for a beginner
• contrast with someone else, as in I don’t drink tea at night

So it is correct, but optional.

In Turkish, many time words can be used directly as adverbs, without a separate word for at, in, or on.

So:

• gece = at night / ночью-like time expression
• bugün = today
• yarın = tomorrow
• sabah = in the morning
• akşam = in the evening

Here, gece functions adverbially, so gece çay içmiyorum means I don’t drink tea at night.

English needs at night, but Turkish often just uses the time noun by itself.

This is a very common question.

Turkish often uses the present continuous form for habits or regular behavior in everyday speech, especially when talking about what someone does or does not do these days or as a personal rule.

So:

• çay içmiyorum = I’m not drinking tea / I don’t drink tea
• gece çay içmiyorum = I don’t drink tea at night

You could also hear:

• Gece çay içmem.

That also means I don’t drink tea at night, but it can sound:

• more general
• more rule-like
• a bit firmer or more definite

So in this sentence, içmiyorum sounds very natural and conversational.

It breaks down like this:

• iç- = drink
• -me- = negative
• -iyor = present continuous
• -um = I

So underlyingly:

iç-me-iyor-um

But in actual form, the e drops before -iyor, giving:

içmiyorum

So the meaning is literally something like:

I am not drinking

And depending on context, that can also mean I don’t drink.

Because çay here is a nonspecific, general object.

In Turkish, the accusative ending often marks a specific/definite direct object.

So:

• çay içmiyorum = I don’t drink tea / I’m not drinking tea
• çayı içmiyorum = I’m not drinking the tea / that specific tea

In this sentence, the speaker means tea in general at night, not a particular cup or particular tea. So çay without the accusative is the natural choice.

Çünkü means because.

It introduces the reason:

• Ben gece çay içmiyorum = main statement
• çünkü sonra uyuyamıyorum = reason

So the structure is:

statement + çünkü + reason

This works quite similarly to English because.

Also, after çünkü, Turkish still keeps its normal clause structure, especially with the verb near the end:

• sonra uyuyamıyorum

Here sonra means afterward, later, or then.

So:

• çünkü sonra uyuyamıyorum = because afterward / then I can’t sleep

It does not mean after followed by a noun here.

Compare:

• sonra = later, afterward
• dersten sonra = after class
• yemekten sonra = after the meal

In your sentence, sonra is being used on its own, meaning later / afterward.

This form expresses inability.

It comes from uyumak = to sleep.

The form is built like this:

• uyu- = sleep
• -ya- = ability/inability pattern
• -ma- = negative
• -yor = present continuous
• -um = I

So:

uyu-ya-ma-yor-um → uyuyamıyorum

This gives the meaning:

I am not able to sleep
which in natural English is simply
I can’t sleep

This is a very common Turkish pattern:

• yapabiliyorum = I can do it
• yapamıyorum = I can’t do it

Likewise:

• uyuyabiliyorum = I can sleep
• uyuyamıyorum = I can’t sleep

This is an important difference.

• uyuyamıyorum = I can’t sleep
• uyumuyorum = I’m not sleeping / I don’t sleep

So:

1. uyuyamıyorum expresses inability

   • I want to sleep, but I cannot

2. uyumuyorum is simply negative

   • I am not sleeping
   • I don’t sleep

In this sentence, the idea is not just I’m not sleeping, but I can’t sleep afterward, so uyuyamıyorum is exactly the right form.

Yes, you could.

• gece = at night
• geceleri = at nights / nights / generally at night

So:

• Gece çay içmiyorum = I don’t drink tea at night
• Geceleri çay içmiyorum = I don’t drink tea at night / I don’t drink tea on nights

Both are natural, but there is a slight nuance:

• gece is a straightforward time expression
• geceleri can sound a bit more habitual or recurring

You might also compare:

• akşam = evening
• gece = night

So if you mean late evening or nighttime specifically, gece fits well here.

Because Turkish is generally a verb-final language.

That means the verb often comes at the end of the clause:

• Ben gece çay içmiyorum
• çünkü sonra uyuyamıyorum

Other elements usually come before the verb, such as:

• subject
• time expressions
• objects
• adverbs

So in the first clause:

• Ben = subject
• gece = time
• çay = object
• içmiyorum = verb

And in the second clause:

• sonra = time/adverb
• uyuyamıyorum = verb

Turkish word order is somewhat flexible, but this is the most neutral and natural order.