Update README.md

To help with the referencing of the dataset, only the xx language tags are currently taken into account and not the xx-xx

README.md

@@ -9,6 +9,8 @@ language_creators:
 languages:
 - en-US
 - es-ES
+- en
+- es
 licenses:
 - cc-by-nc-nd-4.0
 multilinguality: