diff --git a/mumbledj/config.rb b/mumbledj/config.rb
index 650dfe8..578737d 100644
--- a/mumbledj/config.rb
+++ b/mumbledj/config.rb
@@ -124,4 +124,29 @@ ADMIN_MUTE = true
 # DEFAULT VALUE: true
 ADMIN_UNMUTE = true
 
+# ---------------------
+# MESSAGE CONFIGURATION
+# ---------------------
+
+# Message shown to users when they do not have permission to execute a command.
+NO_PERMISSION_MSG = "You do not have permission to execute that command."
+
+# Message shown to users when they try to move the bot to a non-existant channel.
+CHANNEL_DOES_NOT_EXIST_MSG = "The channel you specified does not exist."
+
+# Message shown to users when they attempt to add an invalid URL to the queue.
+INVALID_URL_MSG = "The URL you submitted does not match the required format."
+
+# Message shown to users when they attempt to use the stop command when no music is playing.
+NO_MUSIC_PLAYING_MSG = "There is no music playing at the moment."
+
+# Message shown to users when they issue a command that requires an argument and one was not supplied.
+NO_ARGUMENT_MSG = "The command you issued requires an argument and you did not provide one. Make sure a space exists between the command and the argument."
+
+# Message shown to users when they try to change the volume to a value outside the volume range.
+NOT_IN_VOLUME_RANGE_MSG = "The volume you tried to supply is not in the allowed volume range. The value must be between #{LOWEST_VOLUME} and #{HIGHEST_VOLUME}."
+
+# Message shown to users when they successfully change the volume.
+VOLUME_SUCCESS_MSG = "You have successfully changed the volume to the following: %s."
+
 
diff --git a/mumbledj/mumbledj.rb b/mumbledj/mumbledj.rb
index da90bdc..9cb640d 100644
--- a/mumbledj/mumbledj.rb
+++ b/mumbledj/mumbledj.rb
@@ -9,6 +9,8 @@ require_relative "song_queue"
 # Class that defines MumbleDJ behavior.
 class MumbleDJ
 
+  attr_reader :username, :server_address, :server_port, :default_channel
+
   # Initializes a new instance of MumbleDJ. The parameters are as follows:
   # username: Desired username of the Mumble bot
   # server_address: IP address/web address of Mumble server to connect to
@@ -126,6 +128,8 @@ class MumbleDJ
   def has_permission?(admin_command, sender)
     if ENABLE_ADMINS and admin_command
       return ADMINS.include?(sender)
+    else
+      return true
     end
   end
   
@@ -133,7 +137,7 @@ class MumbleDJ
     if OUTPUT_ENABLED
       puts("#{sender} has added a song to the queue.")
     end
-    if song_add_successful?(url, sender)
+    if @song_queue.add_song?(url, sender)
       @client.text_channel(@client.me.current_channel.name, "<b>#{sender}</b> has added a song to the queue.")
     else
       @client.text_user(sender, "The URL you provided was not valid.")
diff --git a/mumbledj/song.rb b/mumbledj/song.rb
index a7fe303..e5f6253 100644
--- a/mumbledj/song.rb
+++ b/mumbledj/song.rb
@@ -33,6 +33,8 @@ class Song
 end
 
 class YouTubeSong < Song
+
+  attr_reader :url, :submitter, :song_title, :song_duration, :song_thumbnail_url
   
   # Initializes the YouTubeSong object and retrieves the song title,
   # duration, and thumbnail URL from the YouTube API.
@@ -45,4 +47,9 @@ class YouTubeSong < Song
     @song_duration = ""
     @song_thumbnail_url = ""
   end
+  
+  # Downloads the audio for the YouTube video and returns the filename.
+  def download_audio
+  
+  end
 end
diff --git a/mumbledj/song_queue.rb b/mumbledj/song_queue.rb
index 0cafa5e..c7975ee 100644
--- a/mumbledj/song_queue.rb
+++ b/mumbledj/song_queue.rb
@@ -7,6 +7,8 @@ require_relative "song"
 # A specialized SongQueue class that handles queueing/unqueueing songs
 # and other actions.
 class SongQueue
+
+  attr_reader :queue
   
   # Initializes a new song queue.
   def initialize
@@ -16,12 +18,20 @@ class SongQueue
   # Checks if song already exists in the queue, and adds it if it doesn't
   # already exist.
   def add_song?(url, submitter)
-    # TODO: Determine which kind of URL is given (probably using regex),
-    # and instantiate the correct Song object.
-    # Example for a YouTube URL given below.
+    youtube_regex = /(https?:\/\/www\.youtube\.com\/watch\?v=([\d\a_\-]+))
+                    |(https?:\/\/youtube\.com\/watch\?v=([\d\a_\-]+))
+                    |(https?:\/\/youtu\.be\/([\d\a_\-]+))
+                    |(https?:\/\/youtube\.com\/v\/([\d\a_\-]+))
+                    |(https?:\/\/www\.youtube\.com\/v\/([\d\a_\-]+))/x
+    
+    if youtube_regex.match(url)
+      audio_type = "youtube"
+    end
     
     if @queue.empty?
-      song = YouTubeSong.new(url, submitter)
+      if audio_type == "youtube"
+        song = YouTubeSong.new(url, submitter)
+      end
       @queue.push(song)
     else
       @queue.each do |song|
@@ -29,7 +39,9 @@ class SongQueue
           return false
         end
       end
-      song = YouTubeSong.new(url, submitter)
+      if audio_type == "youtube"
+        song = YouTubeSong.new(url, submitter)
+      end
       @queue.push(song)
     end
   end