Website Quality Alert
Unknown content language specification
The code of the content language defined for the web page is unknown.
According to the W3C Internationalization Best Practices, language information is useful for things such as authoring tools, translation tools, accessibility, font selection, page rendering, search, and scripting. In practice, we see that localized search engines (such as google.it) make use of language information, so that missing or incorrect information may have a negative impact of search engine ranking. It is also likely to affect site visitors who use screen readers or spell checkers, in case an input from the user is expected.
Always specify the content language with the correct language code, preferably using the ISO 639 codes.