diff --git a/lib/pronounce.rb b/lib/pronounce.rb
index <HASH>..<HASH> 100644
--- a/lib/pronounce.rb
+++ b/lib/pronounce.rb
@@ -7,7 +7,7 @@ module Pronounce
   class << self
     def how_do_i_pronounce(word)
       @pronouncations ||= build_pronuciation_dictionary
-      word = word.downcase
+      word.downcase!
       if @pronouncations.has_key? word
         @pronouncations[word].syllables.map {|syllable| syllable.to_strings }
       end
diff --git a/spec/pronounce_spec.rb b/spec/pronounce_spec.rb
index <HASH>..<HASH> 100644
--- a/spec/pronounce_spec.rb
+++ b/spec/pronounce_spec.rb
@@ -14,6 +14,10 @@ describe Pronounce do
     it 'returns nil for unknown words' do
       Pronounce.how_do_i_pronounce('beeblebrox').should == nil
     end
+
+    it 'is case insensitive' do
+      Pronounce.how_do_i_pronounce('MoNk').should == [%w{M AH1 NG K}]
+    end
   end
 
   describe '.symbols' do
Tested case insensetivity and used more appropriate method.