docs about the languages

Author: aprosail

README.md

@@ -90,3 +90,21 @@ And if you do want to customize,
 please make sure you've understand the source code.
 Please refer to [`data.ts`](./data.ts) for more details,
 and here's documentation for each item in details.
+
+## About the supported languages
+
+You can find all supported languages
+in the source code of [`data.ts`](./data.ts).
+Each language or language series is an exported const
+that you can import and call.
+
+The languages series are based on the [Unicode](https://unicode.org/charts/).
+Most of the languages are coded manually and some of them are
+generated by several AI models. So that there might be mistakes,
+and the author cannot guarantee the accuracy of the data
+because it's almost impossible for a single person to learn all such languages.
+
+If you are native speaker of one of the those wordless languages
+and you find there are some mistakes,
+or if there's even some wordless languages not included in this package,
+please feel free to open an issue.