Minor modifications

README.md

@@ -114,6 +114,19 @@ German (de), English (en), Finnish (fi), French (fr), Russian (ru), Swedish (sv)
 
 ## Dataset Structure
 
+When you download Opusparcus, you must always indicate the language
+you want to retrieve, for instance:
+
+`data = load_dataset("GEM/opusparcus", lang="de")`
+
+The above command will download the validation and test sets for
+German. If additionally, you want to retrieve training data, you need
+to specify the level of quality you desire, such as:
+
+`data = load_dataset("GEM/opusparcus", lang="fr", quality=90)`
+
+
+
 ### Data Instances
 
 TBA