diff --git a/src/GeneralDeclension.php b/src/GeneralDeclension.php
index ff2d07e..7761c47 100644
--- a/src/GeneralDeclension.php
+++ b/src/GeneralDeclension.php
@@ -2,7 +2,7 @@
 namespace morphos;
 
 abstract class GeneralDeclension implements Cases {
-	abstract static public function isMutable($name);
-	abstract static public function getCases($name);
-	abstract static public function getCase($name, $case);
+	static public function isMutable($name) {}
+	static public function getCases($name) {}
+	static public function getCase($name, $case) {}
 }
diff --git a/src/NamesDeclension.php b/src/NamesDeclension.php
index 9322ce7..4bb98ae 100644
--- a/src/NamesDeclension.php
+++ b/src/NamesDeclension.php
@@ -2,7 +2,7 @@
 namespace morphos;
 
 abstract class NamesDeclension implements Cases, Gender {
-	abstract static public function isMutable($name, $gender);
-	abstract static public function getCases($name, $gender);
-	abstract static public function getCase($name, $case, $gender);
+	static public function isMutable($name, $gender) {}
+	static public function getCases($name, $gender) {}
+	static public function getCase($name, $case, $gender) {}
 }