diff --git a/src/bfu/menu.c b/src/bfu/menu.c
index 24a1433a8..f0a8ee3c4 100644
--- a/src/bfu/menu.c
+++ b/src/bfu/menu.c
@@ -1386,7 +1386,7 @@ new_menu(menu_item_flags_T flags)
 }
 
 void
-add_to_menu(struct menu_item **mi, const char *text, char *rtext,
+add_to_menu(struct menu_item **mi, const char *text, const char *rtext,
 	    main_action_T action_id, menu_func_T func, void *data,
 	    menu_item_flags_T flags)
 {
diff --git a/src/bfu/menu.h b/src/bfu/menu.h
index cc9c1313e..1c41dbc64 100644
--- a/src/bfu/menu.h
+++ b/src/bfu/menu.h
@@ -169,7 +169,7 @@ struct menu {
 struct menu_item *new_menu(menu_item_flags_T);
 
 void
-add_to_menu(struct menu_item **mi, const char *text, char *rtext,
+add_to_menu(struct menu_item **mi, const char *text, const char *rtext,
 	    main_action_T action_id, menu_func_T func, void *data,
 	    menu_item_flags_T flags);
 
diff --git a/src/intl/libintl.c b/src/intl/libintl.c
index 3d66e9672..777e0814c 100644
--- a/src/intl/libintl.c
+++ b/src/intl/libintl.c
@@ -133,7 +133,7 @@ iso639_to_language(const char *iso639)
 
 int system_language = 0;
 
-char *
+const char *
 language_to_iso639(int language)
 {
 	/* Language is "system", we need to extract the index from
diff --git a/src/intl/libintl.h b/src/intl/libintl.h
index 3f4640d6a..324fe79f3 100644
--- a/src/intl/libintl.h
+++ b/src/intl/libintl.h
@@ -148,7 +148,7 @@ extern int name_to_language(const char *name);
 extern int iso639_to_language(const char *iso639);
 
 extern char *language_to_name(int language);
-extern char *language_to_iso639(int language);
+extern const char *language_to_iso639(int language);
 
 extern int get_system_language_index(void);