diff --git a/ontology/saref.ttl b/ontology/saref.ttl
index b6ac638d3b6cde06ca784764afdf83c26a1ccc00..ca2d7dfc355ff690a25a83b2b19566f083d5ead5 100644
--- a/ontology/saref.ttl
+++ b/ontology/saref.ttl
@@ -222,29 +222,25 @@ saref:represents rdf:type owl:ObjectProperty ;
 
 ###  https://w3id.org/saref#hasDescription
 saref:hasDescription rdf:type owl:DatatypeProperty ;
-                     rdfs:range xsd:string ;
-                     rdfs:comment "A relationship providing a description of an entity (e.g., device)"^^xsd:string ;
+                     rdfs:comment "A relationship providing a description of an entity (e.g., device). The value is expected to be a string or a string with language tag."^^xsd:string ;
                      rdfs:label "has description"^^xsd:string .
 
 
 ###  https://w3id.org/saref#hasManufacturer
 saref:hasManufacturer rdf:type owl:DatatypeProperty ;
-                      rdfs:range xsd:string ;
-                      rdfs:comment "A relationship identifying the manufacturer of an entity (e.g., device)"^^xsd:string ;
+                      rdfs:comment "A relationship identifying the manufacturer of an entity (e.g., device). The value is expected to be a string or a string with language tag."^^xsd:string ;
                       rdfs:label "has manufacturer"^^xsd:string .
 
 
 ###  https://w3id.org/saref#hasModel
 saref:hasModel rdf:type owl:DatatypeProperty ;
-               rdfs:range xsd:string ;
-               rdfs:comment "A relationship identifying the model of an entity (e.g., device)"^^xsd:string ;
+               rdfs:comment "A relationship identifying the model of an entity (e.g., device). The value is expected to be a string or a string with language tag."^^xsd:string ;
                rdfs:label "has model"^^xsd:string .
 
 
 ###  https://w3id.org/saref#hasName
 saref:hasName rdf:type owl:DatatypeProperty ;
-              rdfs:range xsd:string ;
-              rdfs:comment "A relationship providing the name of an entity (e.g., device)"^^xsd:string ;
+              rdfs:comment "A relationship providing the name of an entity (e.g., device). The value is expected to be a string or a string with language tag."^^xsd:string ;
               rdfs:label "has name"^^xsd:string .