diff --git a/ChangeLog.txt b/ChangeLog.txt
index a9b5cd49c2..f8e6ffc8e5 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -7,6 +7,12 @@
    Entries may not always be in chronological/commit order.
    See license at the end of file. */
 
+2026-09-01 16:11 UTC+0200 Aleksander Czajczynski (hb fki.pl)
+  * src/lang/l_pl.c
+    * PL language rules normalize that the first letter of a month name
+      and day of the week is not capital. Comparing also to l_cs.c, l_sk.c
+      so it's not a standard in Harbour to keep it Upper.
+
 2026-09-01 15:52 UTC+0200 Aleksander Czajczynski (hb fki.pl)
   * contrib/hbfbird/firebird.c
   * contrib/hbfbird/tfirebrd.prg
diff --git a/src/lang/l_pl.c b/src/lang/l_pl.c
index 2dea5114ed..7eb5f07390 100644
--- a/src/lang/l_pl.c
+++ b/src/lang/l_pl.c
@@ -16,28 +16,28 @@ static HB_LANG s_lang =
 
       /* Month names */
 
-      "Styczeń",
-      "Luty",
-      "Marzec",
-      "Kwiecień",
-      "Maj",
-      "Czerwiec",
-      "Lipiec",
-      "Sierpień",
-      "Wrzesień",
-      "Październik",
-      "Listopad",
-      "Grudzień",
+      "styczeń",
+      "luty",
+      "marzec",
+      "kwiecień",
+      "maj",
+      "czerwiec",
+      "lipiec",
+      "sierpień",
+      "wrzesień",
+      "październik",
+      "listopad",
+      "grudzień",
 
       /* Day names */
 
-      "Niedziela",
-      "Poniedziałek",
-      "Wtorek",
-      "Środa",
-      "Czwartek",
-      "Piątek",
-      "Sobota",
+      "niedziela",
+      "poniedziałek",
+      "wtorek",
+      "środa",
+      "czwartek",
+      "piątek",
+      "sobota",
 
       /* CA-Cl*pper compatible natmsg items */