This might lead us to believe that a simple culture would make use of a simple language, that a complex culture would make use of a complex language, and so on

This problem is too simple

What seems simple to you seems complex to me

Impure drinking water can be a carrier of diseases

The new school is of simple and modern construction

He is not as simple as he seems

The problem is not as simple as it might seem at first sight

With this one exception, it is quite wrong to suppose that a simple culture will also have a simple language

His story was simplicity itself

His story was simplicity itself