diff --git a/schala-lang/language/src/eval.rs b/schala-lang/language/src/eval.rs
index f70a7c0..ff052b3 100644
--- a/schala-lang/language/src/eval.rs
+++ b/schala-lang/language/src/eval.rs
@@ -242,7 +242,7 @@ impl<'a> State<'a> {
 
   fn apply_data_constructor(&mut self, _type_name: Rc<String>, name: Rc<String>, tag: usize, arity: usize, args: Vec<Expr>) -> EvalResult<Node> {
     if arity != args.len() {
-      return Err(format!("Data constructor {} requires {} args", name, arity));
+      return Err(format!("Data constructor {} requires {} arg(s)", name, arity));
     }
 
     let evaled_args = args.into_iter().map(|expr| self.expression(Node::Expr(expr))).collect::<Result<Vec<Node>,_>>()?;