Allowable values for <language> in RSS http://backend.userland.com/discuss/msgReader$16

list

Afrikaans: af
Albanian: sq 
Basque: eu
Belarusian: be
Bulgarian: bg
Catalan: ca
Chinese (Simplified): zh-cn
Chinese (Traditional): zh-tw
Croatian: hr
Czech: cs
Danish: da
Dutch: nl
Dutch (Belgium): nl-be
Dutch (Netherlands): nl-nl
English: en
English (Australia): en-au
English (Belize): en-bz
English (Canada): en-ca
English (Ireland): en-ie
English (Jamaica): en-jm
English (New Zealand): en-nz
English (Phillipines): en-ph
English (South Africa): en-za
English (Trinidad): en-tt
English (United Kingdom): en-gb
English (United States): en-us
English (Zimbabwe): en-zw
Estonian:  et
Faeroese: fo
Finnish: fi
French: fr
French (Belgium): fr-be
French (Canada): fr-ca
French (France): fr-fr
French (Luxembourg): fr-lu
French (Monaco): fr-mc
French (Switzerland): fr-ch
Galician: gl
Gaelic: gd
German: de
German (Austria): de-at
German (Germany): de-de
German (Liechtenstein): de-li
German (Luxembourg): de-lu
German (Switzerland): de-ch
Greek: el
Hawaiian: haw
Hungarian: hu
Icelandic: is
Indonesian: in
Irish: ga
Italian: it
Italian (Italy): it-it
Italian (Switzerland): it-ch
Japanese: ja
Korean: ko
Macedonian: mk
Norwegian: no
Polish: pl
Portuguese: pt
Portuguese (Brazil): pt-br
Portuguese (Portugal): pt-pt
Romanian: ro
Romanian (Moldova): ro-mo
Romanian (Romania): ro-ro
Russian: ru
Russian (Moldova): ru-mo
Russian (Russia): ru-ru
Serbian: sr
Slovak: sk
Slovenian: sl
Spanish: es
Spanish (Argentina): es-ar
Spanish (Bolivia): es-bo
Spanish (Chile): es-cl
Spanish (Colombia): es-co
Spanish (Costa Rica): es-cr
Spanish (Dominican Republic): es-do
Spanish (Ecuador): es-ec
Spanish (El Salvador): es-sv
Spanish (Guatemala): es-gt
Spanish (Honduras): es-hn
Spanish (Mexico): es-mx
Spanish (Nicaragua): es-ni
Spanish (Panama): es-pa
Spanish (Paraguay): es-py
Spanish (Peru): es-pe
Spanish (Puerto Rico): es-pr
Spanish (Spain): es-es
Spanish (Uruguay): es-uy
Spanish (Venezuela)es-ve
Swedish: sv
Swedish (Finland): sv-fi
Swedish (Sweden): sv-se
Turkish: tr
Ukranian: uk

raw

af
sq
eu
be
bg
ca
zh-cn
zh-tw
hr
cs
da
nl
nl-be
nl-nl
en
en-au
en-bz
en-ca
en-ie
en-jm
en-nz
en-ph
en-za
en-tt
en-gb
en-us
en-zw
et
fo
fi
fr
fr-be
fr-ca
fr-fr
fr-lu
fr-mc
fr-ch
gl
gd
de
de-at
de-de
de-li
de-lu
de-ch
el
haw
hu
is
in
ga
it
it-it
it-ch
ja
ko
mk
no
pl
pt
pt-br
pt-pt
ro
ro-mo
ro-ro
ru
ru-mo
ru-ru
sr
sk
sl
es
es-ar
es-bo
es-cl
es-co
es-cr
es-do
es-ec
es-sv
es-gt
es-hn
es-mx
es-ni
es-pa
es-py
es-pe
es-pr
es-es
es-uy
es-ve
sv
sv-fi
sv-se
tr
uk

RSS language codes

java:
Set.of("af", "sq", "eu", "be", "bg", "ca", "zh-cn", "zh-tw", "hr", "cs", "da", "nl", "nl-be", "nl-nl", "en", "en-au", "en-bz", "en-ca", "en-ie", "en-jm", "en-nz", "en-ph", "en-za", "en-tt", "en-gb", "en-us", "en-zw", "et", "fo", "fi", "fr", "fr-be", "fr-ca", "fr-fr", "fr-lu", "fr-mc", "fr-ch", "gl", "gd", "de", "de-at", "de-de", "de-li", "de-lu", "de-ch", "el", "haw", "hu", "is", "in", "ga", "it", "it-it", "it-ch", "ja", "ko", "mk", "no", "pl", "pt", "pt-br", "pt-pt", "ro", "ro-mo", "ro-ro", "ru", "ru-mo", "ru-ru", "sr", "sk", "sl", "es", "es-ar", "es-bo", "es-cl", "es-co", "es-cr", "es-do", "es-ec", "es-sv", "es-gt", "es-hn", "es-mx", "es-ni", "es-pa", "es-py", "es-pe", "es-pr", "es-es", "es-uy", "es-ve", "sv", "sv-fi", "sv-se", "tr", "uk")