This exists for media types ("Accept" HTTP request header) and for language ("Accept-Language" HTTP request header). You can configure your browser to tell it w

This exists for media types ("Accept" HTTP request header) and for language ("Accept-Language" HTTP request header). You can configure your browser to tell it which languages you understand, and your order of preference. You're proposing something like "Accept-Semantic-Complexity", or maybe extend Accept-Language somehow to include acceptable complexity. It could work in principle but I doubt anyone would use it. Many websites already have a tendency to ignore Accept-Language and instead use some fuzzy region detection when they offer multiple languages.