Adam yetmiş yaşında.

In Turkish, the verb to be is often not spoken as a separate word in simple present-tense sentences.

So:

• Adam yetmiş yaşında = The man is seventy years old

In the 3rd person singular, Turkish usually leaves the copula unspoken in this kind of sentence.

Compare:

• Ben yetmiş yaşındayım = I am seventy years old
• Sen yetmiş yaşındasın = You are seventy years old
• O yetmiş yaşında = He/She is seventy years old

So in your sentence, the is is understood.

Adam most commonly means man.

In context, it can mean:

• the man
• a man
• sometimes more loosely the guy

Turkish does not have words exactly like English a/an and the, so the exact meaning depends on context.

So Adam yetmiş yaşında could be understood as:

• The man is seventy years old
• A man is seventy years old
  though in many contexts the man is the more natural translation

Yaşında is the standard Turkish way to say someone's age.

The pattern is:

• [number] yaşında = [number] years old

Examples:

• on yaşında = ten years old
• yirmi yaşında = twenty years old
• yetmiş yaşında = seventy years old

Literally, yaşında is built from yaş (age) plus endings, but as a learner, the most useful thing is to remember it as a set expression:

• X yaşında = X years old

Because Turkish handles numbers differently from English.

In English, we say:

• seventy years old

But in Turkish, after a number, the noun usually stays singular:

• yetmiş yaşında

You do not make yaş plural here.

This is normal in Turkish:

• iki kitap = two books
  literally two book
• üç gün = three days
  literally three day

So yetmiş yaşında is the normal and correct pattern.

A simple pronunciation guide is:

• yetmiş → yet-mish
• yaşında → ya-shun-duh

A few helpful points:

• ş sounds like sh
• ı is a vowel that does not exist exactly in English; it is a dull, relaxed vowel, somewhat like the second vowel in sofa, but not identical

So the whole sentence sounds roughly like:

• ah-DAHM yet-MISH yah-shun-DAH

That is only an approximation, but it is close enough for a beginner.

In this sentence, yes, adam normally refers to a man.

However, in colloquial Turkish, adam can sometimes be used more loosely for person or guy, depending on context. Still, the most straightforward meaning here is:

• The man is seventy years old

If you wanted to say The woman is seventy years old, you would say:

• Kadın yetmiş yaşında

Yes, you can, but it is a slightly different structure.

• Adam yetmiş yaşında = The man is seventy years old
• Adamın yaşı yetmiş = The man's age is seventy

Both are correct, but X yaşında is the more common and natural way to state someone's age in everyday Turkish.

So if you are simply saying how old someone is, Adam yetmiş yaşında is usually the better choice.

The phrase yetmiş yaşında stays the same, but the ending changes depending on the subject.

Examples:

• Ben yetmiş yaşındayım = I am seventy years old
• Sen yetmiş yaşındasın = You are seventy years old
• O yetmiş yaşında = He/She is seventy years old
• Biz yetmiş yaşındayız = We are seventy years old
• Siz yetmiş yaşındasınız = You are seventy years old
• Onlar yetmiş yaşında = They are seventy years old

Notice that o and often onlar can appear without an extra ending in this kind of sentence.

The most neutral word order is:

• Adam yetmiş yaşında

This is a normal statement: The man is seventy years old.

But Turkish word order is somewhat flexible for emphasis.

For example:

• Yetmiş yaşında adam does not mean exactly the same thing.
  It usually means a seventy-year-old man.

So:

• Adam yetmiş yaşında = a full sentence
• Yetmiş yaşında adam = a noun phrase

That difference is important.

Yes. The expression [number] yaşında does not change for gender.

Examples:

• Adam yetmiş yaşında = The man is seventy years old
• Kadın yetmiş yaşında = The woman is seventy years old
• Çocuk yetmiş yaşında would be grammatically possible, though logically strange, because çocuk means child

So the age expression itself is gender-neutral.

Yes. Yetmiş means seventy.

Some nearby numbers for comparison:

• altmış = sixty
• yetmiş = seventy
• seksen = eighty
• doksan = ninety

So:

• Adam altmış yaşında = The man is sixty years old
• Adam yetmiş yaşında = The man is seventy years old
• Adam seksen yaşında = The man is eighty years old

You add the question particle mi:

• Adam yetmiş yaşında mı? = Is the man seventy years old?

The particle is written separately.

Examples:

• O yirmi yaşında mı? = Is he/she twenty years old?
• Kadın elli yaşında mı? = Is the woman fifty years old?

So for your sentence, the question form is:

• Adam yetmiş yaşında mı?