Update runtime files.
diff --git a/runtime/tutor/tutor.utf-8 b/runtime/tutor/tutor.utf-8
index 64a27d1..16207a9 100644
--- a/runtime/tutor/tutor.utf-8
+++ b/runtime/tutor/tutor.utf-8
@@ -12,7 +12,7 @@
 
      ATTENTION:
      The commands in the lessons will modify the text.  Make a copy of this
-     file to practise on (if you started "vimtutor" this is already a copy).
+     file to practice on (if you started "vimtutor" this is already a copy).
 
      It is important to remember that this tutor is set up to teach by
      use.  That means that you need to execute the commands to learn them