diff --git a/allzweckmesser/model.py b/allzweckmesser/model.py
index 73909a3b6f8246f51f7c1369a73512980e31f48f..8e9bd7869f93873bc57886952725a7e67755e254 100644
--- a/allzweckmesser/model.py
+++ b/allzweckmesser/model.py
@@ -63,15 +63,15 @@ def minimal(full_dict:dict):
 
 class Syllable:
 
-    def __init__(self, syllable: str, span: List[int], idx: int,
-                 syllable_length: int, vowel_length: int,
+    def __init__(self, syllable: str, span: List[int], idx: int = None,
+                 syllable_length: int = 1, vowel_length: int = 1,
                  phenomena: dict = None):
         if len(syllable) != span[1] - span[0]:
             raise ValueError('Syllable length does not match syllable span.')
         else:
             self.text = syllable
             self.span = span
-            self.id = idx
+            self.id = idx or None
             self.syllable_length = syllable_length
             self.vowel_length = vowel_length
             self.phenomena = phenomena or dict()