bié zài zhège lùkǒu zhuǎnwān.

别 is used to make a negative command: don’t ...

So:

• 别转弯 = Don’t turn
• 别在这个路口转弯 = Don’t turn at this intersection

It is not the same as 不.

• 不转弯 usually sounds like a statement: not turning / won’t turn
• 别转弯 is an instruction or warning

A close alternative is:

• 不要在这个路口转弯。

That also means Don’t turn at this intersection, but 别 is shorter and very common in spoken Mandarin.

In Mandarin, commands often omit the subject when it is obvious.

So:

• 别在这个路口转弯。
• 你别在这个路口转弯。

Both are possible, but the version without 你 is very natural. The listener is understood from context.

Adding 你 can give a little more emphasis, like You—don’t turn here.

Mandarin usually puts time, place, and other background information before the main verb.

So the structure is:

• 别
  • 在这个路口
    • 转弯

Literally, it is something like:

• Don’t [at this intersection] turn

This is normal Mandarin word order. English often puts the location after the verb, but Mandarin commonly puts it before the verb.

Here 在 is acting like a preposition meaning at / in / on, depending on context.

In this sentence:

• 在这个路口 = at this intersection

So 在 marks where the action happens.

It is worth knowing that 在 can also be a main verb meaning to be located at, but in this sentence it is not the main verb. The main verb is 转弯.

Because 这 and 那 usually need a measure word / classifier before a noun.

So:

• 这 + 个 + 路口 = 这个路口 = this intersection

Here 个 is the classifier.

You can think of it as:

• 这 = this
• 个 = general classifier
• 路口 = intersection

So 这个路口 is the normal way to say this intersection.

路口 means a road junction / intersection.

Literally:

• 路 = road
• 口 = opening, mouth, entrance

Together, 路口 refers to the place where roads meet or open into each other.

A few related words:

• 路口 = intersection, junction
• 十字路口 = crossroads
• 交叉路口 = intersection where roads cross

In everyday speech, 路口 is very common and natural.

In this sentence, 转弯 works as a single verbal expression meaning to turn.

Literally:

• 转 = turn
• 弯 = bend, curve

Together:

• 转弯 = make a turn / turn

It can be used by itself:

• 前面转弯。 = Turn ahead.
• 别转弯。 = Don’t turn.

You can also add direction words:

• 向左转弯 = turn left
• 向右转弯 = turn right

Great question. 转 is a multiple-pronunciation character.

In 转弯, it is pronounced zhuǎn, because it means to turn/change direction.

Examples:

• 转弯 = zhuǎnwān = turn
• 左转 = zuǒ zhuǎn = turn left

The reading zhuàn is used in some other meanings, often involving rotating or turning around in a different sense.

So in this sentence, the correct pronunciation is:

• 转弯 zhuǎnwān

转弯 by itself just means turn. It does not say left or right.

So this sentence simply says not to make a turn at this intersection. The exact direction is not specified.

If you want to specify direction, you can say:

• 别在这个路口左转。 = Don’t turn left at this intersection.
• 别在这个路口右转。 = Don’t turn right at this intersection.

Yes. That is completely natural.

Compare:

• 别在这个路口转弯。
• 不要在这个路口转弯。

Both mean the same thing.

A rough difference:

• 别 = shorter, very common in speech
• 不要 = slightly fuller, sometimes a bit more formal or emphatic

In conversation, 别 is extremely common.

It is usually pronounced zhè ge, with ge in a neutral tone.

So although learners often focus on both syllables equally, in natural speech the second syllable is usually light:

• 这 = zhè
• 个 = ge (neutral tone)

So 这个路口 is commonly said more like:

• zhè ge lùkǒu

not with a strong full tone on 个.

Yes, it is natural, especially as spoken instruction.

For example, a person, a driving teacher, or a GPS could say:

• 别在这个路口转弯。

On an official sign, Chinese often uses a more formal wording such as:

• 此路口禁止转弯。 = Turning at this intersection is prohibited.
• 禁止左转 / 禁止右转。 = No left turn / No right turn

So your sentence is very natural for spoken Mandarin, while signs often sound a bit more formal.