Add language tag

Unfortunately, the Diola has no iso639 code and therefore cannot be referenced on Hugging Face :(

README.md

@@ -144,6 +144,10 @@ dataset_info:
     num_examples: 26387
   download_size: 546144081
   dataset_size: 567773923.639
+language:
+- wo
+- fuc
+- srr
 ---
 
 ### Dataset Summary