Xfce is translated into many languages, as long as someone has taken the effort to create this translation. The translation status pages show you exactly which languages are already covered and which ones still need work or are even missing. Please check out those webpages before inquiring to the mailinglist about translator status for a specific language.

References:

• Language Codes: http://www.loc.gov/standards/iso639-2/php/code_list.php
• Country Codes: http://www.iso.org/iso/country_codes/iso_3166_code_lists/english_country_names_and_code_elements.htm