features.md

 1.  Word features
-Words feature describe different aspects of the words present in the buffer or in the stack.
+  
+Words feature describe different attributes of the words present in the buffer or in the stack.
 They are composed of an *address function* identifying a particular word and an *attribute function* selecting a specific attribute of the word, such as its form, lemma, part of speech ...
 Such features are represented as strings that are the concatenation of the address function and the attribute function.
 
-Address function can be one of the following: 
+The following address function are defined: 
 
 *  **b0** the current word in the buffer 
 *  **b1** the word following b0
@@ -16,3 +17,13 @@ Address function can be one of the following:
 * **s1** the word below s0
 * **s2** the word below s1
 * **s3** the word below s2
+
+The following attribute functions are defined:
+
+* **f** the form the word
+* **l** its lemma
+* **c** its coarse part of speech
+* **p** its part of speech
+* **m** its morphological features
+* **s** its syntactic function
+