diff --git a/rdf/src/main/java/fr/tetras_libre/unltools/rdf/vocabulary/UnlDocumentToRdfConverter.java b/rdf/src/main/java/fr/tetras_libre/unltools/rdf/vocabulary/UnlDocumentToRdfConverter.java
index 6d6c08821b88e5440da55aa590a80947e6fb83fe..83d04c6db0a79b025b2ff708d624e858bf4ec31b 100644
--- a/rdf/src/main/java/fr/tetras_libre/unltools/rdf/vocabulary/UnlDocumentToRdfConverter.java
+++ b/rdf/src/main/java/fr/tetras_libre/unltools/rdf/vocabulary/UnlDocumentToRdfConverter.java
@@ -19,6 +19,7 @@ import static fr.tetras_libre.unltools.rdf.vocabulary.Slugify.slugify;
 
 public class UnlDocumentToRdfConverter {
     private final static String DOMAIN = "http://rdf-unl.org";
+    private final static String Lang = null;
 
     private RelationLabelToUnlPropertyConverter relationLabelToUnlPropertyConverter;
 
@@ -78,12 +79,12 @@ public class UnlDocumentToRdfConverter {
 
                             // Création de l'universalWord dans le dictionnaire
                             var universalWordIndividual = sentenceOntModel.createIndividual(String.format("%s/%s#%s", DOMAIN, uniqId, slugify(uw.getUniversalWord().toString())), UNL.UW_Lexeme);
-                            universalWordIndividual.addLabel(uw.getUniversalWord().toString(), "fr/tetras_libre/unltools/unl");
+                            universalWordIndividual.addLabel(uw.getUniversalWord().toString(), UnlDocumentToRdfConverter.Lang);
 
                             // Création de l'occurence du l'universalWord
                             var universalWordOccurrence = sentenceOntModel.createIndividual(UtilGraphNodeUri.constructGraphNodeUri(sentenceNameSpace, uw),
                                     UNL.UW_Occurrence);
-                            universalWordOccurrence.addLabel(uw.getUniversalWord().toString(), "fr/tetras_libre/unltools/unl");
+                            universalWordOccurrence.addLabel(uw.getUniversalWord().toString(), UnlDocumentToRdfConverter.Lang);
                             this.setSuperstructureWithSubstructure(sentenceOntModel, sentenceIndividual, sentenceOntModel, universalWordOccurrence);
                             sentenceOntModel.add(universalWordOccurrence, UNL.is_occurrence_of, universalWordIndividual);
                             sentenceOntModel.add(universalWordIndividual, UNL.has_occurrence, universalWordOccurrence);
@@ -103,7 +104,7 @@ public class UnlDocumentToRdfConverter {
                                                 UtilGraphNodeUri.constructGraphNodeUri(sentenceNameSpace, graphRefNode),
                                                 UNL.UNL_Scope);
 
-                                        scopeIndividual.addLabel(scopeName, "fr/tetras_libre/unltools/unl");
+                                        scopeIndividual.addLabel(scopeName, UnlDocumentToRdfConverter.Lang);
                                         this.setSuperstructureWithSubstructure(sentenceOntModel, sentenceIndividual, sentenceOntModel, scopeIndividual);
 
                                         GraphExtensions.getRelationWithinScopeStream(graphRefNode.getReferenceNumber(), sentencegraph)