diff --git a/folio/graph.py b/folio/graph.py
index 8e473a0..66320a1 100644
--- a/folio/graph.py
+++ b/folio/graph.py
@@ -659,7 +659,8 @@ def parse_owl_class(self, node: lxml.etree._Element) -> None:
                 lang = child.attrib.get(self.get_ns_tag("xml", "lang"), None)
                 if lang:
                     owl_class.translations[lang] = child.text
-                else:
+                # Always add to alternative_labels for search indexing
+                if child.text not in owl_class.alternative_labels:
                     owl_class.alternative_labels.append(child.text)
 
                 # add triple