Şehirde bir milyon kişi yaşıyor.

Şehir means city. The ending -de is the locative suffix, which means in or at.

So:

• şehir = city
• şehirde = in the city

It is written as one word because -de here is a suffix, not a separate word.

Compare:

• şehirde = in the city
• şehir de = the city too / the city also

This is because of two regular sound rules in Turkish:

• Vowel harmony decides between -de and -da
• Consonant voicing decides between d and t

In şehir, the last vowel is i, which is a front vowel, so the suffix uses the front form: -de / -te, not -da / -ta.

Also, şehir ends in r, which is a voiced consonant, so the suffix uses d, not t.

That gives:

• şehir + de → şehirde

Here it clearly means one, because it is part of the number bir milyon = one million.

In other sentences, bir can also mean a/an, depending on context.

For example:

• bir kitap = a book
• bir milyon = one million

After numbers, Turkish normally uses the singular form of the noun.

So you say:

• bir milyon kişi
• üç öğrenci
• on kitap

not:

• bir milyon kişiler
• üç öğrenciler
• on kitaplar

This is a very important difference from English. In Turkish, the number already shows plurality, so the noun usually stays singular.

Both can refer to people, but they are used a little differently.

• kişi = person, individual; very common in counting, statistics, official language
• insan = human, person, people; more general

In a sentence like this, kişi sounds very natural because it is a number-based statement.

So:

• bir milyon kişi yaşıyor = very natural
• bir milyon insan yaşıyor = also possible, but slightly less statistical/formal in tone

Yaşıyor comes from the dictionary form yaşamak, which means to live.

The ending -iyor is the present continuous ending, but in Turkish this form is also often used for general present situations.

So yaşıyor can mean:

• is living
• lives

depending on context.

In this sentence, natural English could be either:

• One million people live in the city
• One million people are living in the city

The first is usually the more natural English translation.

The verb stem is yaşa-.

When Turkish adds the present continuous ending -(I)yor, the form becomes:

• yaşa- + -ıyor → yaşıyor

So the vowel changes as the word is formed.

This kind of contraction is normal in Turkish verbs.

Useful comparison:

• başlamak → başlıyor
• anlamak → anlıyor
• yaşamak → yaşıyor

This is a very common question.

Even though bir milyon kişi refers to many people, Turkish very often uses a singular verb form with numbered or quantified subjects.

So:

• Bir milyon kişi yaşıyor = standard and natural

Using yaşıyorlar is possible in some kinds of speech, especially when the speaker is thinking of the people more personally, but with numbers and statistical statements, yaşıyor is the normal choice.

So the pattern to remember is:

• iki kişi geldi
• yüz öğrenci bekliyor
• bir milyon kişi yaşıyor

Turkish word order is fairly flexible, but the verb usually stays at the end in a neutral sentence.

Your sentence:

• Şehirde bir milyon kişi yaşıyor.

is completely natural.

You could also say:

• Bir milyon kişi şehirde yaşıyor.

Both are correct, but the emphasis is slightly different:

• Şehirde bir milyon kişi yaşıyor puts the setting in the city first
• Bir milyon kişi şehirde yaşıyor puts one million people first

So the meaning stays the same, but the focus changes a little.

These two sentences are close, but not identical.

• Şehirde bir milyon kişi var = There are one million people in the city
• Şehirde bir milyon kişi yaşıyor = One million people live in the city

Var simply says that something exists / is present.

Yaşıyor specifically says that those people live there.

So yaşıyor is more specific than var.

Here is the structure:

• şehir-de = city-in / in the city
• bir milyon = one million
• kişi = person
• yaşıyor = is living / lives

A very literal English order would be:

• In the city one million person lives/is living

That is not natural English, but it helps show the Turkish structure.

Natural English would be:

• One million people live in the city

A rough pronunciation guide is:

• Şehirde ≈ sheh-heer-deh
• bir ≈ beer
• milyon ≈ mee-lyon
• kişi ≈ kee-shuh
• yaşıyor ≈ yah-shuh-yor

A few useful sound notes:

• ş = sh
• i = a clear ee sound
• ı = a short vowel with no exact English equivalent; it is somewhat like a relaxed uh
• Turkish spelling is quite regular, so pronunciation becomes easier once you learn the letters