diff --git a/language.go b/language.go
index 7eb4714..a7c762a 100644
--- a/language.go
+++ b/language.go
@@ -2,7 +2,9 @@ package astisub
 
 // Languages
 const (
+	LanguageChinese   = "chinese"
 	LanguageEnglish   = "english"
 	LanguageFrench    = "french"
+	LanguageJapanese  = "japanese"
 	LanguageNorwegian = "norwegian"
 )
diff --git a/stl.go b/stl.go
index c0b5929..2d0ea1b 100644
--- a/stl.go
+++ b/stl.go
@@ -108,8 +108,10 @@ const (
 
 // STL country codes
 const (
-	stlCountryCodeFrance = "FRA"
-	stlCountryCodeNorway = "NOR"
+	stlCountryCodeChinese = "CHN"
+	stlCountryCodeFrance  = "FRA"
+	stlCountryCodeJapan   = "JPN"
+	stlCountryCodeNorway  = "NOR"
 )
 
 // STL cumulative status
@@ -142,18 +144,22 @@ const (
 
 // STL language codes
 const (
+	stlLanguageCodeChinese   = "75"
 	stlLanguageCodeEnglish   = "09"
 	stlLanguageCodeFrench    = "0F"
+	stllanguageCodeJapanese  = "69"
 	stlLanguageCodeNorwegian = "1E"
 )
 
 // STL language mapping
 var stlLanguageMapping = astikit.NewBiMap().
+	Set(stlLanguageCodeChinese, LanguageChinese).
 	Set(stlLanguageCodeEnglish, LanguageEnglish).
 	Set(stlLanguageCodeFrench, LanguageFrench).
+	Set(stllanguageCodeJapanese, LanguageJapanese).
 	Set(stlLanguageCodeNorwegian, LanguageNorwegian)
 
-// STL timecode status
+	// STL timecode status
 const (
 	stlTimecodeStatusNotIntendedForUse = "0"
 	stlTimecodeStatusIntendedForUse    = "1"
diff --git a/ttml.go b/ttml.go
index 9dd0521..2e8046b 100644
--- a/ttml.go
+++ b/ttml.go
@@ -19,15 +19,19 @@ import (
 
 // TTML languages
 const (
+	ttmlLanguageChinese   = "zh"
 	ttmlLanguageEnglish   = "en"
+	ttmlLanguageJapanese  = "ja"
 	ttmlLanguageFrench    = "fr"
 	ttmlLanguageNorwegian = "no"
 )
 
 // TTML language mapping
 var ttmlLanguageMapping = astikit.NewBiMap().
+	Set(ttmlLanguageChinese, LanguageChinese).
 	Set(ttmlLanguageEnglish, LanguageEnglish).
 	Set(ttmlLanguageFrench, LanguageFrench).
+	Set(ttmlLanguageJapanese, LanguageJapanese).
 	Set(ttmlLanguageNorwegian, LanguageNorwegian)
 
 // TTML Clock Time Frames and Offset Time