filters\ContentNegotiator $languages

A list of supported languages. The array keys are the supported language variants (e.g. en-GB, en-US), while the array values are the corresponding language codes (e.g. en, de) recognized by the application.

Array keys are not always required. When an array value does not have a key, the matching of the requested language will be based on a language fallback mechanism. For example, a value of en will match en, en_US, en-US, en-GB, etc.

If this property is empty or not set, language negotiation will be skipped.