diff --git a/README.md b/README.md
index b80365d..5be77d3 100644
--- a/README.md
+++ b/README.md
@@ -124,6 +124,7 @@ a.humanize() // 'a few minutes'
 ##### Own rules / i18n
 
 If you want to pass a different humanize function you can.
+The order of the array is important. The first match will return, like in a standard server router. The first argument is a function that takes the duration and returns a boolean. The second takes also matched duration and returns a string for the user.
 
 ###### Example
 
@@ -140,4 +141,4 @@ a.subtract(1, 'day')
 a.humanize(humanizer) // '1 day'
 a.subtract(12, 'hours')
 a.humanize(humanizer) // 'catch all, below 1 day'
-```
\ No newline at end of file
+```