Re: [css3-selectors] [css4-selectors] [CSS21] pseudo grammar conflicts with BCP 47 (RFC4647) for :lang()

Bjoern Hoehrmann:

> In CSS 2.1 the definition is "…" with no mention of any wildcards and BCP 47 is referenced only informatively in a note unrelated to matching.

You’re right about the definition. I think it is overly specific, though, and doesn’t match its intention, i.e. being compatible with BCP47.