diff --git a/lcl/forms.pp b/lcl/forms.pp
index f01053116a..72a269cb45 100644
--- a/lcl/forms.pp
+++ b/lcl/forms.pp
@@ -1610,8 +1610,8 @@ type
     procedure IntfThemeOptionChange(AThemeServices: TThemeServices; AOption: TThemeOption);
 
     function IsRightToLeft: Boolean;
-    function IsRTLLang(ALang: string): Boolean;
-    function Direction(ALang: string): TBiDiMode;
+    function IsRTLLang(const ALang: string): Boolean;
+    function Direction(const ALang: string): TBiDiMode;
   public
     // on key down
     procedure DoArrowKey(AControl: TWinControl; var Key: Word; Shift: TShiftState);
diff --git a/lcl/include/application.inc b/lcl/include/application.inc
index f7f9169a7f..49f3e00c25 100644
--- a/lcl/include/application.inc
+++ b/lcl/include/application.inc
@@ -2391,7 +2391,7 @@ begin
   if Assigned(FOnActionUpdate) then FOnActionUpdate(TheAction, Result);
 end;
 
-function TApplication.IsRTLLang(ALang: String): Boolean;
+function TApplication.IsRTLLang(const ALang: String): Boolean;
 var
  lng : String;
  p   : word;
@@ -2436,7 +2436,7 @@ begin
             ;
 end;
 
-function TApplication.Direction(ALang: String): TBiDiMode;
+function TApplication.Direction(const ALang: String): TBiDiMode;
 const
   BidiModeMap: array[Boolean] of TBiDiMode = (bdLeftToRight, bdRightToLeft);
 begin