diff --git a/spot/twaalgos/word.cc b/spot/twaalgos/word.cc
index 61a005264..9db5c7ed5 100644
--- a/spot/twaalgos/word.cc
+++ b/spot/twaalgos/word.cc
@@ -190,7 +190,7 @@ namespace spot
 	  word_parse_error(word, word.size(),
 			   "A twa_word must contain a cycle");
 	if (word[ind] == '}')
-	  word_parse_error(word, ind, "Expected ';' delimiter :"
+	  word_parse_error(word, ind, "Expected ';' delimiter: "
 			   "'}' stands for ending a cycle");
 	// Exract formula, convert it to bdd and add it to the prefix sequence
 	extract_bdd(tw->prefix);
@@ -211,7 +211,7 @@ namespace spot
 	  break;
 	if (i == std::string::npos)
 	  word_parse_error(word, ind + 1,
-			   "Missing end of cycle character : '}'");
+			   "Missing end of cycle character: '}'");
       }
     if (ind != word.size() - 1)
       word_parse_error(word, ind + 1, "Input should be finished after cycle");
diff --git a/tests/python/word.ipynb b/tests/python/word.ipynb
index 04f54e2f4..5a3f4cd67 100644
--- a/tests/python/word.ipynb
+++ b/tests/python/word.ipynb
@@ -349,10 +349,10 @@
      "outputs": [
       {
        "ename": "SyntaxError",
-       "evalue": "\n>>> a; b; c}\n           ^\nExpected ';' delimiter :'}' stands for ending a cycle\n (<string>)",
+       "evalue": "\n>>> a; b; c}\n           ^\nExpected ';' delimiter: '}' stands for ending a cycle\n (<string>)",
        "output_type": "pyerr",
        "traceback": [
-        "\u001b[0;36m  File \u001b[0;32m\"<string>\"\u001b[0;36m, line \u001b[0;32munknown\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m \n>>> a; b; c}\n           ^\nExpected ';' delimiter :'}' stands for ending a cycle\n\n"
+        "\u001b[0;36m  File \u001b[0;32m\"<string>\"\u001b[0;36m, line \u001b[0;32munknown\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m \n>>> a; b; c}\n           ^\nExpected ';' delimiter: '}' stands for ending a cycle\n\n"
        ]
       }
      ],
@@ -517,4 +517,4 @@
    "metadata": {}
   }
  ]
-}
\ No newline at end of file
+}