diff --git a/alib2data/src/alphabet/Alphabet.hpp b/alib2data/src/alphabet/Alphabet.hpp
index ec1fd58226d0b5a3b0bbbf3be030c14c8c1aa7b1..d3d6e23f4bd6852238effa6c446b230bfddea426 100644
--- a/alib2data/src/alphabet/Alphabet.hpp
+++ b/alib2data/src/alphabet/Alphabet.hpp
@@ -73,7 +73,8 @@ public:
 		for ( const SymbolType & symbol : removed )
 			remove ( symbol );
 
-		data = std::move ( symbols );
+		for ( const SymbolType & symbol : symbols )
+			add ( std::move ( symbols ) );
 	}
 
 	/**