diff --git a/README.md b/README.md
index 9bdd5d1..ce6c160 100644
--- a/README.md
+++ b/README.md
@@ -32,4 +32,5 @@ The only I/O supported is the keyboard and screen but 40-column text, LORES
 and HIRES graphics are all supported.
 
 ApplePy currently requires Pygame (although there is a minimal applepy_curses.py
-that uses curses to display text mode only).
\ No newline at end of file
+that uses curses to display text mode only) and numpy (just for an array for
+speaker sounds)