Update README.md

README.md

@@ -40,6 +40,8 @@ results = metric.compute(predictions=[translated_text], references=[[ground_trut
 print(f"{results=}")
 ```
 
+Note that we didn't provide `FastTokenizer` because we added special tokens and `FastTokenizer` will output `<UNK>` tokens. Please set `use_fast=False` when loading the tokenizer.
+
 ## Resources
 - Homepage: [Vision-Braille](https://vision-braille.com/)
 - Repository: [Github](https://github.com/AlanYWu/ChineseBrailleTranslation)