Documentation: words parameter documented for voice files.

docs/voices.md

 # Voice Files
 
+# Table of contents
+
 - [Contents of Voice Files](#contents-of-voice-files)
   - [Identification Attributes](#identification-attributes)
     - [name](#name)
     - [breath](#breath)
     - [breathw](#breathw)
     - [speed](#speed)
+    - [words](#words)
   - [Language Attributes](#language-attributes)
     - [phonemes](#phonemes)
     - [dictionary](#dictionary)
 can be used if a language voice seems faster or slower compared to other
 voices.
 
+#### words
+
+    words <integer value> <integer value>
+
+The first parameter  puts a pause between all words, the value can be **0** to **4**.
+
+The second parameter adds a short pause if a word ends with a vowel and 
+the next words starts with a vowel. Values may be:
+
+* **0**  no pause   
+**1**  no pause, but the two vowels are kept separate.  
+**2**  short pause.
+
+For example:
+
+    words 0 1
+
+Will put a short pause between two words where the first word end with a 
+vowel and the next start with a vowel. 
+
+
 ### Language Attributes
 
 #### phonemes