diff --git a/buildings-start_date.json b/buildings-start_date.json
index a5b50559..6b9bb535 100644
--- a/buildings-start_date.json
+++ b/buildings-start_date.json
@@ -111,11 +111,11 @@
         "  </tr>",
         "  <tr>",
         "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\", \"start_date\": \"xxx\" }))|raw }}</td>",
-        "    <td>unparseable start_date</td>",
+        "    <td>{{ repoTrans('date format not understood') }}</td>",
         "  </tr>",
         "  <tr>",
         "    <td>{{ markerPolygon(evaluate({ \"building\": \"yes\" }))|raw }}</td>",
-        "    <td>no start_date</td>",
+        "    <td>{{ trans('unknown') }}</td>",
         "  </tr>",
         "</table>"
     ]
diff --git a/lang/ast.json b/lang/ast.json
index f50bfdbe..716071e8 100644
--- a/lang/ast.json
+++ b/lang/ast.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "Fábriques",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/ca.json b/lang/ca.json
index 8fc41283..c3f136de 100644
--- a/lang/ca.json
+++ b/lang/ca.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/cs.json b/lang/cs.json
index d5545457..f8ee143f 100644
--- a/lang/cs.json
+++ b/lang/cs.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "Továrny",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/de.json b/lang/de.json
index e3e9e406..100cd38f 100644
--- a/lang/de.json
+++ b/lang/de.json
@@ -85,5 +85,6 @@
     "category:water": "Gewässer",
     "category:wikipedia": "Wikipedia",
     "category:works": "Fabriken",
-    "category:xmas": "Weihnachten"
+    "category:xmas": "Weihnachten",
+    "date format not understood": "Datumsformat nicht erkannt"
 }
diff --git a/lang/el.json b/lang/el.json
index ecceb29f..f4ed8b1b 100644
--- a/lang/el.json
+++ b/lang/el.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/en.json b/lang/en.json
index c9a3519b..e719bc92 100644
--- a/lang/en.json
+++ b/lang/en.json
@@ -85,5 +85,6 @@
     "category:water": "Waterbodies",
     "category:wikipedia": "Wikipedia",
     "category:works": "Works",
-    "category:xmas": "Christmas"
+    "category:xmas": "Christmas",
+    "date format not understood": ""
 }
diff --git a/lang/es.json b/lang/es.json
index 1e74bf06..48d6d0fd 100644
--- a/lang/es.json
+++ b/lang/es.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/et.json b/lang/et.json
index d86c5c3b..798a575f 100644
--- a/lang/et.json
+++ b/lang/et.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/fr.json b/lang/fr.json
index 3713ae89..3c535cb2 100644
--- a/lang/fr.json
+++ b/lang/fr.json
@@ -85,5 +85,6 @@
     "category:water": "Hydrographie",
     "category:wikipedia": "Wikipédia",
     "category:works": "Zones industrielles",
-    "category:xmas": "Noël"
+    "category:xmas": "Noël",
+    "date format not understood": ""
 }
diff --git a/lang/hu.json b/lang/hu.json
index bbacb7b7..35b4d601 100644
--- a/lang/hu.json
+++ b/lang/hu.json
@@ -85,5 +85,6 @@
     "category:water": "Vizek",
     "category:wikipedia": "Wikipédia",
     "category:works": "Üzemek",
-    "category:xmas": "Karácsony"
+    "category:xmas": "Karácsony",
+    "date format not understood": ""
 }
diff --git a/lang/it.json b/lang/it.json
index 7960f3a6..245647c5 100644
--- a/lang/it.json
+++ b/lang/it.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "Fabbriche",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/ja.json b/lang/ja.json
index 32a1fe93..f409ba75 100644
--- a/lang/ja.json
+++ b/lang/ja.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "工場",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/nl.json b/lang/nl.json
index 41e2d31e..c4d8ad3c 100644
--- a/lang/nl.json
+++ b/lang/nl.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "Fabrieken",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/pl.json b/lang/pl.json
index 1877ff04..174566e2 100644
--- a/lang/pl.json
+++ b/lang/pl.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/pt-br.json b/lang/pt-br.json
index 7b57f8ab..b6f1086e 100644
--- a/lang/pt-br.json
+++ b/lang/pt-br.json
@@ -85,5 +85,6 @@
     "category:water": "Hidrografia",
     "category:wikipedia": "Wikipédia",
     "category:works": "Fábricas",
-    "category:xmas": "Natal"
+    "category:xmas": "Natal",
+    "date format not understood": ""
 }
diff --git a/lang/pt.json b/lang/pt.json
index 770d2ba7..7a6f7799 100644
--- a/lang/pt.json
+++ b/lang/pt.json
@@ -85,5 +85,6 @@
     "category:water": "Massas de água",
     "category:wikipedia": "Wikipédia",
     "category:works": "Fábricas",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/ro.json b/lang/ro.json
index 08ce2fe0..a5572e43 100644
--- a/lang/ro.json
+++ b/lang/ro.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/ru.json b/lang/ru.json
index f321c053..073a42b0 100644
--- a/lang/ru.json
+++ b/lang/ru.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "Промышленность",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/template.json b/lang/template.json
index b2231d56..29c5c658 100644
--- a/lang/template.json
+++ b/lang/template.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }
diff --git a/lang/uk.json b/lang/uk.json
index 6b01ebe4..eb3ad066 100644
--- a/lang/uk.json
+++ b/lang/uk.json
@@ -85,5 +85,6 @@
     "category:water": "",
     "category:wikipedia": "",
     "category:works": "",
-    "category:xmas": ""
+    "category:xmas": "",
+    "date format not understood": ""
 }