diff --git a/README.md b/README.md
index 2ce54d8..78ce160 100644
--- a/README.md
+++ b/README.md
@@ -32,9 +32,9 @@ Fit a specific token against a string. `render_string()` uses this function inte
 typedef void (*attribute_callback_t)(const char * const string, const int length, void * const attributes);
 ```
 The type used for defining appropriate callbacks for render\_string().
-+ string     - string to be outputed
-+ length     - number of characters that matched a highlighting rule
-+ attributes - arbitrary data associated with the matched rule; intended to hold color/font information for example
++ string     - string to be processed (probably printed)
++ length     - number of characters to be processed from _string_
++ attributes - arbitrary data associated with the matched token; intended to hold color/font information for example; if no token was matched NULL will be passed
 
 
 ```C