diff --git a/src/mp_ui_alerts.cpp b/src/mp_ui_alerts.cpp
index de33c7ffbad..c169cf036c3 100644
--- a/src/mp_ui_alerts.cpp
+++ b/src/mp_ui_alerts.cpp
@@ -14,7 +14,7 @@
 */
 
 /**
- * This namespace provides handlers which play the sounds / notificaitons
+ * This namespace provides handlers which play the sounds / notifications
  * for various mp server events, depending on the preference configuration.
  */
 
@@ -30,10 +30,10 @@
 #include <string>
 #include <vector>
 
-namespace mp_ui_alerts {
-
-namespace {
-
+namespace mp_ui_alerts
+{
+namespace
+{
 bool lobby_pref(const std::string& id)
 {
 	return preferences::get(id + "_lobby", get_def_pref_lobby(id));
@@ -49,22 +49,42 @@ bool notif_pref(const std::string& id)
 	return preferences::get(id + "_notif", get_def_pref_notif(id));
 }
 
+const std::string _player_joins = "player_joins";
+const std::string _player_leaves = "player_leaves";
+const std::string _private_message = "private_message";
+const std::string _friend_message = "friend_message";
+const std::string _public_message = "public_message";
+const std::string _server_message = "server_message";
+const std::string _ready_for_start = "ready_for_start";
+const std::string _game_has_begun = "game_has_begun";
+const std::string _turn_changed = "turn_changed";
+const std::string _game_created = "game_created";
 } // end anonymous namespace
 
-const std::vector<std::string> items {"player_joins", "player_leaves", "private_message", "friend_message", "public_message", "server_message", "ready_for_start", "game_has_begun", "turn_changed", "game_created"};
+const std::vector<std::string> items{
+	_player_joins,
+	_player_leaves,
+	_private_message,
+	_friend_message,
+	_public_message,
+	_server_message,
+	_ready_for_start,
+	_game_has_begun,
+	_turn_changed,
+	_game_created,
+};
 
-void game_created(const std::string & scenario, const std::string & name)
+void game_created(const std::string& scenario, const std::string& name)
 {
-	std::string id = "game_created";
-	if (!lobby_pref(id)) {
-		return ;
+	if(!lobby_pref(_game_created)) {
+		return;
 	}
 
-	if (sound_pref(id)) {
+	if(sound_pref(_game_created)) {
 		sound::play_UI_sound(game_config::sounds::game_created);
 	}
 
-	if (notif_pref(id)) {
+	if(notif_pref(_game_created)) {
 		const std::string message = VGETTEXT("A game ($name|, $scenario|) has been created", {{"name", name}, {"scenario", scenario}});
 		desktop::notifications::send(_("Wesnoth"), message, desktop::notifications::OTHER);
 	}
@@ -72,133 +92,148 @@ void game_created(const std::string & scenario, const std::string & name)
 
 void player_joins(bool is_lobby)
 {
-	std::string id = "player_enters";
-	if (is_lobby && !lobby_pref(id)) {
-		return ;
+	if(is_lobby && !lobby_pref(_player_joins)) {
+		return;
 	}
-	if (sound_pref(id)) {
+
+	if(sound_pref(_player_joins)) {
 		sound::play_UI_sound(game_config::sounds::player_joins);
 	}
-	if (notif_pref(id)) {
+
+	if(notif_pref(_player_joins)) {
 		desktop::notifications::send(_("Wesnoth"), _("A player has joined"), desktop::notifications::OTHER);
 	}
 }
 
 void player_leaves(bool is_lobby)
 {
-	std::string id = "player_leaves";
-	if (is_lobby && !lobby_pref(id)) {
-		return ;
+	if(is_lobby && !lobby_pref(_player_leaves)) {
+		return;
 	}
-	if (sound_pref(id)) {
+
+	if(sound_pref(_player_leaves)) {
 		sound::play_UI_sound(game_config::sounds::player_leaves);
 	}
-	if (notif_pref(id)) {
+
+	if(notif_pref(_player_leaves)) {
 		desktop::notifications::send(_("Wesnoth"), _("A player has left"), desktop::notifications::OTHER);
 	}
 }
 
-void public_message(bool is_lobby, const std::string & sender, const std::string & message)
+void public_message(bool is_lobby, const std::string& sender, const std::string& message)
 {
-	std::string id = "public_message";
-	if (is_lobby && !lobby_pref(id)) {
-		return ;
+	if(is_lobby && !lobby_pref(_public_message)) {
+		return;
 	}
-	if (sound_pref(id)) {
+
+	if(sound_pref(_public_message)) {
 		sound::play_UI_sound(game_config::sounds::public_message);
 	}
-	if (notif_pref(id)) {
+
+	if(notif_pref(_public_message)) {
 		desktop::notifications::send(sender, message, desktop::notifications::CHAT);
 	}
 }
 
-void friend_message(bool is_lobby, const std::string & sender, const std::string & message)
+void friend_message(bool is_lobby, const std::string& sender, const std::string& message)
 {
-	std::string id = "friend_message";
-	if (is_lobby && !lobby_pref(id)) {
-		return ;
+	if(is_lobby && !lobby_pref(_friend_message)) {
+		return;
 	}
-	if (sound_pref(id)) {
+
+	if(sound_pref(_friend_message)) {
 		sound::play_UI_sound(game_config::sounds::friend_message);
 	}
-	if (notif_pref(id)) {
+
+	if(notif_pref(_friend_message)) {
 		desktop::notifications::send(sender, message, desktop::notifications::CHAT);
 	}
 }
 
-void private_message(bool is_lobby, const std::string & sender, const std::string & message)
+void private_message(bool is_lobby, const std::string& sender, const std::string& message)
 {
-	std::string id = "private_message";
-	if (is_lobby && !lobby_pref(id)) {
-		return ;
+	if(is_lobby && !lobby_pref(_private_message)) {
+		return;
 	}
-	if (sound_pref(id)) {
+
+	if(sound_pref(_private_message)) {
 		sound::play_UI_sound(game_config::sounds::private_message);
 	}
-	if (notif_pref(id)) {
+
+	if(notif_pref(_private_message)) {
 		desktop::notifications::send(sender, message, desktop::notifications::CHAT);
 	}
 }
 
-void server_message(bool is_lobby, const std::string & sender, const std::string & message)
+void server_message(bool is_lobby, const std::string& sender, const std::string& message)
 {
-	std::string id = "server_message";
-	if (is_lobby && !lobby_pref(id)) {
-		return ;
+	if(is_lobby && !lobby_pref(_server_message)) {
+		return;
 	}
-	if (sound_pref(id)) {
+
+	if(sound_pref(_server_message)) {
 		sound::play_UI_sound(game_config::sounds::server_message);
 	}
-	if (notif_pref(id)) {
+
+	if(notif_pref(_server_message)) {
 		desktop::notifications::send(sender, message, desktop::notifications::CHAT);
 	}
 }
 
 void ready_for_start()
 {
-	std::string id = "ready_for_start";
-	if (sound_pref(id)) {
-		if (preferences::UI_sound_on()) {
-			sound::play_bell(game_config::sounds::ready_for_start); //this is play_bell instead of play_UI_sound to economize on sound channels. UI only has two sounds, and turn bell has a dedicated channel.
+	if(sound_pref(_ready_for_start)) {
+		if(preferences::UI_sound_on()) {
+			// this is play_bell instead of play_UI_sound to economize on sound channels. UI only has two
+			// sounds, and turn bell has a dedicated channel.
+			sound::play_bell(game_config::sounds::ready_for_start);
 		}
 	}
-	if (notif_pref(id)) {
+
+	if(notif_pref(_ready_for_start)) {
 		desktop::notifications::send(_("Wesnoth"), _("Ready to start!"), desktop::notifications::OTHER);
 	}
 }
 
 void game_has_begun()
 {
-	std::string id = "game_has_begun";
-	if (sound_pref(id)) {
+	if(sound_pref(_game_has_begun)) {
 		sound::play_UI_sound(game_config::sounds::game_has_begun);
 	}
-	if (notif_pref(id)) {
-		desktop::notifications::send(_("Wesnoth"), _ ("Game has begun!"), desktop::notifications::OTHER);
+
+	if(notif_pref(_game_has_begun)) {
+		desktop::notifications::send(_("Wesnoth"), _("Game has begun!"), desktop::notifications::OTHER);
 	}
 }
 
-void turn_changed(const std::string & player_name)
+void turn_changed(const std::string& player_name)
 {
-	std::string id = "turn_changed";
-	if (notif_pref(id)) {
+	if(notif_pref(_turn_changed)) {
 		utils::string_map player;
 		player["name"] = player_name;
 		desktop::notifications::send(_("Turn changed"), VGETTEXT("$name has taken control", player), desktop::notifications::TURN_CHANGED);
 	}
 }
 
-bool get_def_pref_sound(const std::string & id) {
-	return (id != "public_message" && id != "friend_message");
+bool get_def_pref_sound(const std::string& id)
+{
+	return (id != _public_message && id != _friend_message);
 }
 
-bool get_def_pref_notif(const std::string & id) {
-	return (desktop::notifications::available() && (id == "private_message" || id == "ready_for_start" || id == "game_has_begun" || id == "turn_changed" || id == "game_created"));
+bool get_def_pref_notif(const std::string& id)
+{
+	return (desktop::notifications::available() && (
+		id == _private_message ||
+		id == _ready_for_start ||
+		id == _game_has_begun ||
+		id == _turn_changed ||
+		id == _game_created
+	));
 }
 
-bool get_def_pref_lobby(const std::string & id) {
-	return (id == "private_message" || id == "server_message" || id == "game_created");
+bool get_def_pref_lobby(const std::string& id)
+{
+	return (id == _private_message || id == _server_message || id == _game_created);
 }
 
-
 } // end namespace mp_ui_alerts