currently some POSIX locales uses a variant tag. Example ca-ES@valencia, or sr_RS.UTF-8@latin. Please, improve the Hunspell searching dictionary. So, ca-ES.dic or ca-ES-valencia.dic will be used, according to sytem locale. I think the best approach is uses BCP 47 internally at Hunspell.
Some useful related links:
Plesae, take this feature request. Some "big" projects need it (like LibreOffice, Firefox or Thunderbird...). Thanks in advance.