diff --git a/pandoc.cabal b/pandoc.cabal
index 888a0570b..2a34d5680 100644
--- a/pandoc.cabal
+++ b/pandoc.cabal
@@ -510,6 +510,7 @@ library
                    Text.Pandoc.Readers.Docx.StyleMap,
                    Text.Pandoc.Readers.Docx.Fields,
                    Text.Pandoc.Readers.LaTeX.Parsing,
+                   Text.Pandoc.Readers.LaTeX.Lang,
                    Text.Pandoc.Readers.Odt.Base,
                    Text.Pandoc.Readers.Odt.Namespaces,
                    Text.Pandoc.Readers.Odt.StyleReader,
diff --git a/src/Text/Pandoc/Readers/LaTeX.hs b/src/Text/Pandoc/Readers/LaTeX.hs
index 1af82246e..816fa35de 100644
--- a/src/Text/Pandoc/Readers/LaTeX.hs
+++ b/src/Text/Pandoc/Readers/LaTeX.hs
@@ -72,6 +72,8 @@ import Text.Pandoc.Parsing hiding (blankline, many, mathDisplay, mathInline,
 import Text.Pandoc.Readers.LaTeX.Types (ExpansionPoint (..), Macro (..),
                                         ArgSpec (..), Tok (..), TokType (..))
 import Text.Pandoc.Readers.LaTeX.Parsing
+import Text.Pandoc.Readers.LaTeX.Lang (polyglossiaLangToBCP47,
+                                       babelLangToBCP47)
 import Text.Pandoc.Shared
 import qualified Text.Pandoc.Translations as Translations
 import Text.Pandoc.Walk
@@ -2265,137 +2267,3 @@ setDefaultLanguage = do
          setTranslations l
          updateState $ setMeta "lang" $ str (renderLang l)
          return mempty
-
-polyglossiaLangToBCP47 :: M.Map String (String -> Lang)
-polyglossiaLangToBCP47 = M.fromList
-  [ ("arabic", \o -> case filter (/=' ') o of
-       "locale=algeria"    -> Lang "ar" "" "DZ" []
-       "locale=mashriq"    -> Lang "ar" "" "SY" []
-       "locale=libya"      -> Lang "ar" "" "LY" []
-       "locale=morocco"    -> Lang "ar" "" "MA" []
-       "locale=mauritania" -> Lang "ar" "" "MR" []
-       "locale=tunisia"    -> Lang "ar" "" "TN" []
-       _                   -> Lang "ar" "" "" [])
-  , ("german", \o -> case filter (/=' ') o of
-       "spelling=old" -> Lang "de" "" "DE" ["1901"]
-       "variant=austrian,spelling=old"
-                       -> Lang "de" "" "AT" ["1901"]
-       "variant=austrian" -> Lang "de" "" "AT" []
-       "variant=swiss,spelling=old"
-                       -> Lang "de" "" "CH" ["1901"]
-       "variant=swiss" -> Lang "de" "" "CH" []
-       _ -> Lang "de" "" "" [])
-  , ("lsorbian", \_ -> Lang "dsb" "" "" [])
-  , ("greek", \o -> case filter (/=' ') o of
-       "variant=poly"    -> Lang "el" "" "polyton" []
-       "variant=ancient" -> Lang "grc" "" "" []
-       _                 -> Lang "el" "" "" [])
-  , ("english", \o -> case filter (/=' ') o of
-       "variant=australian" -> Lang "en" "" "AU" []
-       "variant=canadian"   -> Lang "en" "" "CA" []
-       "variant=british"    -> Lang "en" "" "GB" []
-       "variant=newzealand" -> Lang "en" "" "NZ" []
-       "variant=american"   -> Lang "en" "" "US" []
-       _                    -> Lang "en" "" "" [])
-  , ("usorbian", \_ -> Lang "hsb" "" "" [])
-  , ("latin", \o -> case filter (/=' ') o of
-       "variant=classic" -> Lang "la" "" "" ["x-classic"]
-       _                 -> Lang "la" "" "" [])
-  , ("slovenian", \_ -> Lang "sl" "" "" [])
-  , ("serbianc", \_ -> Lang "sr" "cyrl" "" [])
-  , ("pinyin", \_ -> Lang "zh" "Latn" "" ["pinyin"])
-  , ("afrikaans", \_ -> Lang "af" "" "" [])
-  , ("amharic", \_ -> Lang "am" "" "" [])
-  , ("assamese", \_ -> Lang "as" "" "" [])
-  , ("asturian", \_ -> Lang "ast" "" "" [])
-  , ("bulgarian", \_ -> Lang "bg" "" "" [])
-  , ("bengali", \_ -> Lang "bn" "" "" [])
-  , ("tibetan", \_ -> Lang "bo" "" "" [])
-  , ("breton", \_ -> Lang "br" "" "" [])
-  , ("catalan", \_ -> Lang "ca" "" "" [])
-  , ("welsh", \_ -> Lang "cy" "" "" [])
-  , ("czech", \_ -> Lang "cs" "" "" [])
-  , ("coptic", \_ -> Lang "cop" "" "" [])
-  , ("danish", \_ -> Lang "da" "" "" [])
-  , ("divehi", \_ -> Lang "dv" "" "" [])
-  , ("esperanto", \_ -> Lang "eo" "" "" [])
-  , ("spanish", \_ -> Lang "es" "" "" [])
-  , ("estonian", \_ -> Lang "et" "" "" [])
-  , ("basque", \_ -> Lang "eu" "" "" [])
-  , ("farsi", \_ -> Lang "fa" "" "" [])
-  , ("finnish", \_ -> Lang "fi" "" "" [])
-  , ("french", \_ -> Lang "fr" "" "" [])
-  , ("friulan", \_ -> Lang "fur" "" "" [])
-  , ("irish", \_ -> Lang "ga" "" "" [])
-  , ("scottish", \_ -> Lang "gd" "" "" [])
-  , ("ethiopic", \_ -> Lang "gez" "" "" [])
-  , ("galician", \_ -> Lang "gl" "" "" [])
-  , ("hebrew", \_ -> Lang "he" "" "" [])
-  , ("hindi", \_ -> Lang "hi" "" "" [])
-  , ("croatian", \_ -> Lang "hr" "" "" [])
-  , ("magyar", \_ -> Lang "hu" "" "" [])
-  , ("armenian", \_ -> Lang "hy" "" "" [])
-  , ("interlingua", \_ -> Lang "ia" "" "" [])
-  , ("indonesian", \_ -> Lang "id" "" "" [])
-  , ("icelandic", \_ -> Lang "is" "" "" [])
-  , ("italian", \_ -> Lang "it" "" "" [])
-  , ("japanese", \_ -> Lang "jp" "" "" [])
-  , ("khmer", \_ -> Lang "km" "" "" [])
-  , ("kurmanji", \_ -> Lang "kmr" "" "" [])
-  , ("kannada", \_ -> Lang "kn" "" "" [])
-  , ("korean", \_ -> Lang "ko" "" "" [])
-  , ("lao", \_ -> Lang "lo" "" "" [])
-  , ("lithuanian", \_ -> Lang "lt" "" "" [])
-  , ("latvian", \_ -> Lang "lv" "" "" [])
-  , ("malayalam", \_ -> Lang "ml" "" "" [])
-  , ("mongolian", \_ -> Lang "mn" "" "" [])
-  , ("marathi", \_ -> Lang "mr" "" "" [])
-  , ("dutch", \_ -> Lang "nl" "" "" [])
-  , ("nynorsk", \_ -> Lang "nn" "" "" [])
-  , ("norsk", \_ -> Lang "no" "" "" [])
-  , ("nko", \_ -> Lang "nqo" "" "" [])
-  , ("occitan", \_ -> Lang "oc" "" "" [])
-  , ("panjabi", \_ -> Lang "pa" "" "" [])
-  , ("polish", \_ -> Lang "pl" "" "" [])
-  , ("piedmontese", \_ -> Lang "pms" "" "" [])
-  , ("portuguese", \_ -> Lang "pt" "" "" [])
-  , ("romansh", \_ -> Lang "rm" "" "" [])
-  , ("romanian", \_ -> Lang "ro" "" "" [])
-  , ("russian", \_ -> Lang "ru" "" "" [])
-  , ("sanskrit", \_ -> Lang "sa" "" "" [])
-  , ("samin", \_ -> Lang "se" "" "" [])
-  , ("slovak", \_ -> Lang "sk" "" "" [])
-  , ("albanian", \_ -> Lang "sq" "" "" [])
-  , ("serbian", \_ -> Lang "sr" "" "" [])
-  , ("swedish", \_ -> Lang "sv" "" "" [])
-  , ("syriac", \_ -> Lang "syr" "" "" [])
-  , ("tamil", \_ -> Lang "ta" "" "" [])
-  , ("telugu", \_ -> Lang "te" "" "" [])
-  , ("thai", \_ -> Lang "th" "" "" [])
-  , ("turkmen", \_ -> Lang "tk" "" "" [])
-  , ("turkish", \_ -> Lang "tr" "" "" [])
-  , ("ukrainian", \_ -> Lang "uk" "" "" [])
-  , ("urdu", \_ -> Lang "ur" "" "" [])
-  , ("vietnamese", \_ -> Lang "vi" "" "" [])
-  ]
-
-babelLangToBCP47 :: String -> Maybe Lang
-babelLangToBCP47 s =
-  case s of
-       "austrian" -> Just $ Lang "de" "" "AT" ["1901"]
-       "naustrian" -> Just $ Lang "de" "" "AT" []
-       "swissgerman" -> Just $ Lang "de" "" "CH" ["1901"]
-       "nswissgerman" -> Just $ Lang "de" "" "CH" []
-       "german" -> Just $ Lang "de" "" "DE" ["1901"]
-       "ngerman" -> Just $ Lang "de" "" "DE" []
-       "lowersorbian" -> Just $ Lang "dsb" "" "" []
-       "uppersorbian" -> Just $ Lang "hsb" "" "" []
-       "polutonikogreek" -> Just $ Lang "el" "" "" ["polyton"]
-       "slovene" -> Just $ Lang "sl" "" "" []
-       "australian" -> Just $ Lang "en" "" "AU" []
-       "canadian" -> Just $ Lang "en" "" "CA" []
-       "british" -> Just $ Lang "en" "" "GB" []
-       "newzealand" -> Just $ Lang "en" "" "NZ" []
-       "american" -> Just $ Lang "en" "" "US" []
-       "classiclatin" -> Just $ Lang "la" "" "" ["x-classic"]
-       _ -> fmap ($ "") $ M.lookup s polyglossiaLangToBCP47
diff --git a/src/Text/Pandoc/Readers/LaTeX/Lang.hs b/src/Text/Pandoc/Readers/LaTeX/Lang.hs
new file mode 100644
index 000000000..9b57c98fd
--- /dev/null
+++ b/src/Text/Pandoc/Readers/LaTeX/Lang.hs
@@ -0,0 +1,173 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+{-
+Copyright (C) 2018 John MacFarlane <jgm@berkeley.edu>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+-}
+
+{- |
+   Module      : Text.Pandoc.Readers.LaTeX.Lang
+   Copyright   : Copyright (C) 2018 John MacFarlane
+   License     : GNU GPL, version 2 or above
+
+   Maintainer  : John MacFarlane <jgm@berkeley.edu>
+   Stability   : alpha
+   Portability : portable
+
+Functions for parsing polyglossia and babel language specifiers to
+BCP47 'Lang'.
+-}
+module Text.Pandoc.Readers.LaTeX.Lang
+  ( polyglossiaLangToBCP47
+  , babelLangToBCP47
+  )
+where
+import Prelude
+import qualified Data.Map as M
+import Text.Pandoc.BCP47 (Lang(..))
+
+polyglossiaLangToBCP47 :: M.Map String (String -> Lang)
+polyglossiaLangToBCP47 = M.fromList
+  [ ("arabic", \o -> case filter (/=' ') o of
+       "locale=algeria"    -> Lang "ar" "" "DZ" []
+       "locale=mashriq"    -> Lang "ar" "" "SY" []
+       "locale=libya"      -> Lang "ar" "" "LY" []
+       "locale=morocco"    -> Lang "ar" "" "MA" []
+       "locale=mauritania" -> Lang "ar" "" "MR" []
+       "locale=tunisia"    -> Lang "ar" "" "TN" []
+       _                   -> Lang "ar" "" "" [])
+  , ("german", \o -> case filter (/=' ') o of
+       "spelling=old" -> Lang "de" "" "DE" ["1901"]
+       "variant=austrian,spelling=old"
+                       -> Lang "de" "" "AT" ["1901"]
+       "variant=austrian" -> Lang "de" "" "AT" []
+       "variant=swiss,spelling=old"
+                       -> Lang "de" "" "CH" ["1901"]
+       "variant=swiss" -> Lang "de" "" "CH" []
+       _ -> Lang "de" "" "" [])
+  , ("lsorbian", \_ -> Lang "dsb" "" "" [])
+  , ("greek", \o -> case filter (/=' ') o of
+       "variant=poly"    -> Lang "el" "" "polyton" []
+       "variant=ancient" -> Lang "grc" "" "" []
+       _                 -> Lang "el" "" "" [])
+  , ("english", \o -> case filter (/=' ') o of
+       "variant=australian" -> Lang "en" "" "AU" []
+       "variant=canadian"   -> Lang "en" "" "CA" []
+       "variant=british"    -> Lang "en" "" "GB" []
+       "variant=newzealand" -> Lang "en" "" "NZ" []
+       "variant=american"   -> Lang "en" "" "US" []
+       _                    -> Lang "en" "" "" [])
+  , ("usorbian", \_ -> Lang "hsb" "" "" [])
+  , ("latin", \o -> case filter (/=' ') o of
+       "variant=classic" -> Lang "la" "" "" ["x-classic"]
+       _                 -> Lang "la" "" "" [])
+  , ("slovenian", \_ -> Lang "sl" "" "" [])
+  , ("serbianc", \_ -> Lang "sr" "cyrl" "" [])
+  , ("pinyin", \_ -> Lang "zh" "Latn" "" ["pinyin"])
+  , ("afrikaans", \_ -> Lang "af" "" "" [])
+  , ("amharic", \_ -> Lang "am" "" "" [])
+  , ("assamese", \_ -> Lang "as" "" "" [])
+  , ("asturian", \_ -> Lang "ast" "" "" [])
+  , ("bulgarian", \_ -> Lang "bg" "" "" [])
+  , ("bengali", \_ -> Lang "bn" "" "" [])
+  , ("tibetan", \_ -> Lang "bo" "" "" [])
+  , ("breton", \_ -> Lang "br" "" "" [])
+  , ("catalan", \_ -> Lang "ca" "" "" [])
+  , ("welsh", \_ -> Lang "cy" "" "" [])
+  , ("czech", \_ -> Lang "cs" "" "" [])
+  , ("coptic", \_ -> Lang "cop" "" "" [])
+  , ("danish", \_ -> Lang "da" "" "" [])
+  , ("divehi", \_ -> Lang "dv" "" "" [])
+  , ("esperanto", \_ -> Lang "eo" "" "" [])
+  , ("spanish", \_ -> Lang "es" "" "" [])
+  , ("estonian", \_ -> Lang "et" "" "" [])
+  , ("basque", \_ -> Lang "eu" "" "" [])
+  , ("farsi", \_ -> Lang "fa" "" "" [])
+  , ("finnish", \_ -> Lang "fi" "" "" [])
+  , ("french", \_ -> Lang "fr" "" "" [])
+  , ("friulan", \_ -> Lang "fur" "" "" [])
+  , ("irish", \_ -> Lang "ga" "" "" [])
+  , ("scottish", \_ -> Lang "gd" "" "" [])
+  , ("ethiopic", \_ -> Lang "gez" "" "" [])
+  , ("galician", \_ -> Lang "gl" "" "" [])
+  , ("hebrew", \_ -> Lang "he" "" "" [])
+  , ("hindi", \_ -> Lang "hi" "" "" [])
+  , ("croatian", \_ -> Lang "hr" "" "" [])
+  , ("magyar", \_ -> Lang "hu" "" "" [])
+  , ("armenian", \_ -> Lang "hy" "" "" [])
+  , ("interlingua", \_ -> Lang "ia" "" "" [])
+  , ("indonesian", \_ -> Lang "id" "" "" [])
+  , ("icelandic", \_ -> Lang "is" "" "" [])
+  , ("italian", \_ -> Lang "it" "" "" [])
+  , ("japanese", \_ -> Lang "jp" "" "" [])
+  , ("khmer", \_ -> Lang "km" "" "" [])
+  , ("kurmanji", \_ -> Lang "kmr" "" "" [])
+  , ("kannada", \_ -> Lang "kn" "" "" [])
+  , ("korean", \_ -> Lang "ko" "" "" [])
+  , ("lao", \_ -> Lang "lo" "" "" [])
+  , ("lithuanian", \_ -> Lang "lt" "" "" [])
+  , ("latvian", \_ -> Lang "lv" "" "" [])
+  , ("malayalam", \_ -> Lang "ml" "" "" [])
+  , ("mongolian", \_ -> Lang "mn" "" "" [])
+  , ("marathi", \_ -> Lang "mr" "" "" [])
+  , ("dutch", \_ -> Lang "nl" "" "" [])
+  , ("nynorsk", \_ -> Lang "nn" "" "" [])
+  , ("norsk", \_ -> Lang "no" "" "" [])
+  , ("nko", \_ -> Lang "nqo" "" "" [])
+  , ("occitan", \_ -> Lang "oc" "" "" [])
+  , ("panjabi", \_ -> Lang "pa" "" "" [])
+  , ("polish", \_ -> Lang "pl" "" "" [])
+  , ("piedmontese", \_ -> Lang "pms" "" "" [])
+  , ("portuguese", \_ -> Lang "pt" "" "" [])
+  , ("romansh", \_ -> Lang "rm" "" "" [])
+  , ("romanian", \_ -> Lang "ro" "" "" [])
+  , ("russian", \_ -> Lang "ru" "" "" [])
+  , ("sanskrit", \_ -> Lang "sa" "" "" [])
+  , ("samin", \_ -> Lang "se" "" "" [])
+  , ("slovak", \_ -> Lang "sk" "" "" [])
+  , ("albanian", \_ -> Lang "sq" "" "" [])
+  , ("serbian", \_ -> Lang "sr" "" "" [])
+  , ("swedish", \_ -> Lang "sv" "" "" [])
+  , ("syriac", \_ -> Lang "syr" "" "" [])
+  , ("tamil", \_ -> Lang "ta" "" "" [])
+  , ("telugu", \_ -> Lang "te" "" "" [])
+  , ("thai", \_ -> Lang "th" "" "" [])
+  , ("turkmen", \_ -> Lang "tk" "" "" [])
+  , ("turkish", \_ -> Lang "tr" "" "" [])
+  , ("ukrainian", \_ -> Lang "uk" "" "" [])
+  , ("urdu", \_ -> Lang "ur" "" "" [])
+  , ("vietnamese", \_ -> Lang "vi" "" "" [])
+  ]
+
+babelLangToBCP47 :: String -> Maybe Lang
+babelLangToBCP47 s =
+  case s of
+       "austrian" -> Just $ Lang "de" "" "AT" ["1901"]
+       "naustrian" -> Just $ Lang "de" "" "AT" []
+       "swissgerman" -> Just $ Lang "de" "" "CH" ["1901"]
+       "nswissgerman" -> Just $ Lang "de" "" "CH" []
+       "german" -> Just $ Lang "de" "" "DE" ["1901"]
+       "ngerman" -> Just $ Lang "de" "" "DE" []
+       "lowersorbian" -> Just $ Lang "dsb" "" "" []
+       "uppersorbian" -> Just $ Lang "hsb" "" "" []
+       "polutonikogreek" -> Just $ Lang "el" "" "" ["polyton"]
+       "slovene" -> Just $ Lang "sl" "" "" []
+       "australian" -> Just $ Lang "en" "" "AU" []
+       "canadian" -> Just $ Lang "en" "" "CA" []
+       "british" -> Just $ Lang "en" "" "GB" []
+       "newzealand" -> Just $ Lang "en" "" "NZ" []
+       "american" -> Just $ Lang "en" "" "US" []
+       "classiclatin" -> Just $ Lang "la" "" "" ["x-classic"]
+       _ -> fmap ($ "") $ M.lookup s polyglossiaLangToBCP47