diff --git a/ChangeLog b/ChangeLog
index f4b2726f12..74a3d73c41 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2018-01-29  Rafal Luzynski  <digitalfreak@lingonborough.com>
+
+	[BZ #10871]
+	* localedata/locales/be_BY (mon): Rename to...
+	(alt_mon): This, then synchronize with CLDR (nominative case).
+	(abmon): Rename to...
+	(ab_alt_mon): This, then synchronize with CLDR (nominative case).
+	(mon): Import from CLDR (genitive case).
+	(abmon): Likewise.
+	* localedata/locales/be_BY@latin (mon): Rename to...
+	(alt_mon): This.
+	(mon): Add, proper genitive forms provided by Viktar Siarheichyk.
+
+	* localedata/locales/be_BY@latin (lang_name): Reworded to
+	"biełaruskaja mova".
+
 2018-01-29  Rafal Luzynski  <digitalfreak@lingonborough.com>
 
 	[BZ #10871]
diff --git a/localedata/locales/be_BY b/localedata/locales/be_BY
index 77f0e2a216..ccc22b9dc2 100644
--- a/localedata/locales/be_BY
+++ b/localedata/locales/be_BY
@@ -117,30 +117,54 @@ abday   "<U041D><U044F><U0434>";/
         "<U0427><U0446><U0432>";/
         "<U041F><U044F><U0442>";/
         "<U0421><U0443><U0431>"
-mon     "<U0421><U0442><U0443><U0434><U0437><U0435><U043D><U044C>";/
-        "<U041B><U044E><U0442><U044B>";/
-        "<U0421><U0430><U043A><U0430><U0432><U0456><U043A>";/
-        "<U041A><U0440><U0430><U0441><U0430><U0432><U0456><U043A>";/
-        "<U041C><U0430><U0439>";/
-        "<U0427><U044D><U0440><U0432><U0435><U043D><U044C>";/
-        "<U041B><U0456><U043F><U0435><U043D><U044C>";/
-        "<U0416><U043D><U0456><U0432><U0435><U043D><U044C>";/
-        "<U0412><U0435><U0440><U0430><U0441><U0435><U043D><U044C>";/
-        "<U041A><U0430><U0441><U0442><U0440><U044B><U0447><U043D><U0456><U043A>";/
-        "<U041B><U0456><U0441><U0442><U0430><U043F><U0430><U0434>";/
-        "<U0421><U043D><U0435><U0436><U0430><U043D><U044C>"
-abmon   "<U0421><U0442><U0434>";/
-        "<U041B><U044E><U0442>";/
-        "<U0421><U0430><U043A>";/
-        "<U041A><U0440><U0441>";/
-        "<U041C><U0430><U0439>";/
-        "<U0427><U044D><U0440>";/
-        "<U041B><U0456><U043F>";/
-        "<U0416><U043D><U0432>";/
-        "<U0412><U0440><U0441>";/
-        "<U041A><U0441><U0442>";/
-        "<U041B><U0456><U0441>";/
-        "<U0421><U043D><U0436>"
+alt_mon "<U0441><U0442><U0443><U0434><U0437><U0435><U043D><U044C>";/
+        "<U043B><U044E><U0442><U044B>";/
+        "<U0441><U0430><U043A><U0430><U0432><U0456><U043A>";/
+        "<U043A><U0440><U0430><U0441><U0430><U0432><U0456><U043A>";/
+        "<U043C><U0430><U0439>";/
+        "<U0447><U044D><U0440><U0432><U0435><U043D><U044C>";/
+        "<U043B><U0456><U043F><U0435><U043D><U044C>";/
+        "<U0436><U043D><U0456><U0432><U0435><U043D><U044C>";/
+        "<U0432><U0435><U0440><U0430><U0441><U0435><U043D><U044C>";/
+        "<U043A><U0430><U0441><U0442><U0440><U044B><U0447><U043D><U0456><U043A>";/
+        "<U043B><U0456><U0441><U0442><U0430><U043F><U0430><U0434>";/
+        "<U0441><U043D><U0435><U0436><U0430><U043D><U044C>"
+mon     "<U0441><U0442><U0443><U0434><U0437><U0435><U043D><U044F>";/
+        "<U043B><U044E><U0442><U0430><U0433><U0430>";/
+        "<U0441><U0430><U043A><U0430><U0432><U0456><U043A><U0430>";/
+        "<U043A><U0440><U0430><U0441><U0430><U0432><U0456><U043A><U0430>";/
+        "<U043C><U0430><U044F>";/
+        "<U0447><U044D><U0440><U0432><U0435><U043D><U044F>";/
+        "<U043B><U0456><U043F><U0435><U043D><U044F>";/
+        "<U0436><U043D><U0456><U045E><U043D><U044F>";/
+        "<U0432><U0435><U0440><U0430><U0441><U043D><U044F>";/
+        "<U043A><U0430><U0441><U0442><U0440><U044B><U0447><U043D><U0456><U043A><U0430>";/
+        "<U043B><U0456><U0441><U0442><U0430><U043F><U0430><U0434><U0430>";/
+        "<U0441><U043D><U0435><U0436><U043D><U044F>"
+ab_alt_mon "<U0441><U0442><U0443>";/
+        "<U043B><U044E><U0442>";/
+        "<U0441><U0430><U043A>";/
+        "<U043A><U0440><U0430>";/
+        "<U043C><U0430><U0439>";/
+        "<U0447><U044D><U0440>";/
+        "<U043B><U0456><U043F>";/
+        "<U0436><U043D><U0456>";/
+        "<U0432><U0435><U0440>";/
+        "<U043A><U0430><U0441>";/
+        "<U043B><U0456><U0441>";/
+        "<U0441><U043D><U0435>"
+abmon   "<U0441><U0442><U0443>";/
+        "<U043B><U044E><U0442>";/
+        "<U0441><U0430><U043A>";/
+        "<U043A><U0440><U0430>";/
+        "<U043C><U0430><U044F>";/
+        "<U0447><U044D><U0440>";/
+        "<U043B><U0456><U043F>";/
+        "<U0436><U043D><U0456>";/
+        "<U0432><U0435><U0440>";/
+        "<U043A><U0430><U0441>";/
+        "<U043B><U0456><U0441>";/
+        "<U0441><U043D><U0435>"
 d_t_fmt "%a %d %b %Y %T"
 d_fmt     "%d.%m.%Y"
 t_fmt     "%T"
diff --git a/localedata/locales/be_BY@latin b/localedata/locales/be_BY@latin
index dbddbeb6f9..43b13cc278 100644
--- a/localedata/locales/be_BY@latin
+++ b/localedata/locales/be_BY@latin
@@ -85,7 +85,7 @@ abmon   "Stu";/
         "Kas";/
         "Lis";/
         "<U015A>ni"
-mon     "Studzie<U0144>";/
+alt_mon	"Studzie<U0144>";/
 	"Luty";/
 	"Sakavik";/
 	"Krasavik";/
@@ -97,6 +97,18 @@ mon     "Studzie<U0144>";/
 	"Kastry<U010D>nik";/
 	"Listapad";/
 	"<U015A>nie<U017E>a<U0144>"
+mon	"studzienia";/
+	"lutaha";/
+	"sakavika";/
+	"krasavika";/
+	"maja";/
+	"<U010D>ervienia";/
+	"lipienia";/
+	"<U017E>ni<U016D>nia";/
+	"viera<U015B>nia";/
+	"kastry<U010D>nika";/
+	"listapada";/
+	"<U015B>nie<U017E>nia"
 am_pm     "";""
 d_t_fmt "%a %d %b %Y %T"
 d_fmt     "%d.%m.%Y"
@@ -144,7 +156,7 @@ country_ab2 "BY"
 country_ab3 "BLR"
 country_num 112
 country_car    "BY"
-lang_name    "byelaruskaya mova"
+lang_name    "bie<U0142>aruskaja mova"
 lang_ab      "be"
 lang_term    "bel"
 lang_lib    "bel"