Arkadaşım gelecek ay evlenecek.

Arkadaşım means my friend.

It is made of:

• arkadaş = friend
• -ım = my

So Turkish often adds possession directly to the noun instead of using a separate word like my.

Because Turkish usually shows possession with a suffix on the noun.

So instead of saying something like my friend with two separate words, Turkish says:

• arkadaş = friend
• arkadaşım = my friend

This is very common in Turkish:

• ev = house

• evim = my house

• kitap = book
• kitabım = my book

So -ım / -im / -um / -üm and related forms are possessive endings, chosen according to vowel harmony and sound rules.

Gelecek ay means next month or more literally the coming month.

It is made of:

• gelecek = coming / next
• ay = month

So this phrase functions like a time expression.

Not exactly in this sentence.

By itself, gelecek can be a verb form meaning he/she/it will come from gelmek = to come.

But in gelecek ay, it is being used like an adjective meaning coming or next:

• gelecek ay = next month
• gelecek hafta = next week
• gelecek yıl = next year

So in this sentence, gelecek is describing ay.

Evlenecek means will get married.

Its dictionary form is evlenmek = to get married.

Breakdown:

• evlen- = get married
• -ecek = future tense suffix

So:

• evlenmek = to get married
• evlenecek = he/she will get married

In this sentence, because the subject is arkadaşım, it means:

• My friend will get married

Because evlenmek usually means to get married, not to marry someone directly.

For an English speaker, this is an important difference.

• Arkadaşım evlenecek. = My friend will get married.

If you want to say marry someone, Turkish often expresses that differently, for example with biriyle evlenmek:

• Ayşe Ali’yle evlendi. = Ayşe got married to Ali.

So evlenmek is not usually used like English marry with a direct object.

Turkish often leaves out subject pronouns when they are not necessary.

The verb form and context are usually enough.

So instead of saying:

• O gelecek ay evlenecek. = He/She will get married next month.

Turkish can simply say:

• Gelecek ay evlenecek. = He/She will get married next month.

In your sentence, the subject is already stated as arkadaşım, so there is no need for o.

Because Turkish normally puts the main verb at the end of the sentence.

So the structure here is:

• Arkadaşım = subject
• gelecek ay = time expression
• evlenecek = verb

This is a very typical Turkish pattern:

Subject + time/place/other information + verb

For example:

• Ben yarın geleceğim. = I will come tomorrow.
• Onlar İstanbul’da yaşıyor. = They live in Istanbul.

Yes, Turkish word order is flexible, but changing it usually changes the emphasis.

The neutral version is:

• Arkadaşım gelecek ay evlenecek.

You could also say:

• Gelecek ay arkadaşım evlenecek.

This still means the same basic thing, but now gelecek ay is more emphasized.

So Turkish can move elements around, but the verb often still stays at the end.

That is because of vowel harmony.

The Turkish future tense suffix has two main forms:

• -ecek
• -acak

Which one appears depends on the vowels in the word.

Examples:

• gelmek → gelecek
• evlenmek → evlenecek
• bakmak → bakacak
• olmak → olacak

So evlenecek uses -ecek because that is the vowel-harmonic form that fits evlen-.

Yes, in this sentence it is singular: my friend.

If you wanted my friends, you would say:

• arkadaşlarım = my friends

Breakdown:

• arkadaş = friend
• -lar = plural
• -ım = my

So:

• arkadaşım = my friend
• arkadaşlarım = my friends

No. Turkish does not have articles exactly like English a/an and the.

So arkadaşım simply means my friend, without needing an article.

Likewise:

• ay = month / the month, depending on context

Turkish relies a lot on context instead of articles.

You would say:

• Arkadaşım gelecek ay evlenmeyecek.

This means:

• My friend will not get married next month.

Here, the negative marker appears before the future ending:

• evlenme- = not get married
• -yecek = future

So:

• evlenecek = will get married
• evlenmeyecek = will not get married

You can say:

• Arkadaşım gelecek ay evlenecek mi?

This means:

• Will my friend get married next month?

The question particle is mi, and it is written separately.

So:

• Evlenecek. = He/She will get married.
• Evlenecek mi? = Will he/she get married?

In Turkish, the third person singular often has no extra personal ending in many tense forms.

Compare:

• Ben evleneceğim. = I will get married.
• Sen evleneceksin. = You will get married.
• O evlenecek. = He/She will get married.

So for third person singular, evlenecek by itself is complete.

Since arkadaşım is third person singular, evlenecek is exactly the right form.

Normally, no.

Arkadaş usually means friend. Depending on context, it can sometimes mean a companion or partner in casual speech, but if you want to clearly say boyfriend or girlfriend, Turkish usually uses more specific expressions, such as:

• erkek arkadaşım = my boyfriend / my male friend
• kız arkadaşım = my girlfriend / my female friend

So on its own, arkadaşım is best understood as my friend.

Yes, it is completely natural.

It is simple, clear, and follows normal Turkish sentence structure:

• Arkadaşım = subject
• gelecek ay = time expression
• evlenecek = verb at the end

A native speaker would understand it immediately.