Language Tag

[sokil]

https://tools.ietf.org/html/rfc5646.html

langtag       = language
                 ["-" script]

 language      = 2*3ALPHA            ; shortest ISO 639 code
                 ["-" extlang]       ; sometimes followed by
                                     ; extended language subtags
               / 4ALPHA              ; or reserved for future use
               / 5*8ALPHA            ; or registered language subtag

 script        = 4ALPHA              ; ISO 15924 code

pt-BR - português do Brasil