このビルには不特定多数の人が出入りするって英語でなんて言うの？

不特定多数=An unspecified large amount.

Hello!

✰ to "pass through this building" = to enter and/or exit the building.
Therefore, "Many people enter and exit this building."

✰ "all kinds of people" = different people/people of different types

I hope this helps! Good luck!! ✰✰

A phrase to signify different types of people would be:
A wide range
A vast range
Different people
And a way of saying that they enter and go out of a building you can say:
'Use this building;
'Have access to this building'

"used by" means people do stuff there alot.

"Many" means a large number.

"Different people" means various ages, both men and woman and people with different occupations.

1. All kinds = all types
2. all and sundry = everyone: "I don't want all and sundry knowing about our problems."
3. This comments that there are no restrictions for entry to the building

The two sentences you see provided above are excellent ways to express to your listener that a particular building has many different people going in and out. In each sentence you will notice the noun stranger. This word means a person that we do not know. This word is common in our everyday conversation and it would make a great addition to your vocabulary.

"A wide range of people have access to this building."
wide range = a set of different things of the same general type.
access = the means or opportunity to approach or enter a place.;to be able to use a particular object or place.

"Many types of people enter and exit this building."
types = a category of people or things having common characteristics.;varieties;kinds of people.

When you want to explain that people enter and exit a building a lot, then you can explain in the following ways:
-A lot of people pass through this building.
-This building has a lot of people coming in and out
-This is a busy building. People come in and out all the time.