This document provides guidance on using audio in computer-assisted language learning (CALL). It discusses best practices for recording, formatting, and storing audio files to be used in CALL projects. Key recommendations include using mp3 format, sampling rates of 22 kHz, and bit rates of 16 bits or higher. The document also covers issues to consider for audio content, such as appropriate language styles for the learner group, clear instructional focus, and avoiding outdated or regionally specific language. Overall, the document aims to help educators create high-quality audio files and select appropriate audio content for CALL.

1. Computer-Assisted Language Learning
Audio
Thom Thibeault, Ph.D.
Samford University
English Language Learner Institute
Birmingham, AL
USA

2. Why Use Audio in CALL?
• Multimodal learning
• Benefits auditory learners
• Improves pronunciation
• Improves listening comprehension

3. Cone of Learning

4. Where do audio samples come from?
• Record them yourself with a computer
• Rip them from CDs
• Digital recorders
• Take them from Web sites (radio plays)
• Extract them from videos
• Buy / free download (LibriVox)

5. Where do audio samples come from?
Record them yourself.
• Audacity
• Media.io
Anyone wanting to make their own recordings should know about Audacity. It's free, easy to use, and works on every computer
system. Audacity needs the LAME plug-in to save files in mp3 format. If you don't want to install the LAME plug-in, you can save
Audacity files in the wav format and then convert them to mp3 with Switch or some other audio conversion program. Mp3 files are
much smaller than wav files! This is important if you're going to use the files on the Web. There are also Web-based applications
that don’t require you to download software. When you record, you can use the computer's internal microphone or use a USB
microphone plugged into your computer's USB port.

6. Where do audio samples come from?
Rip them.
• Copyright issues?
• Public Domain?
• Textbook supplement?
Some foreign language textbooks include materials on CD. You might take files from a CD and convert them to the mp3
format. You can then use the mp3 files in PowerPoint presentations, hypermedia learning units and other ways. We'll explore
the possibilities later on.

7. Where do audio samples come from?
Digital recorders
You can make high-quality digital audio recordings with devices such as the inexpensive Olympus digital audio recorder or the
expensive Zoom digital audio recorder. Generally, the more expensive the device, the better the sound quality. Some of these
devices store the recordings on SD memory cards, exactly like the ones used in digital cameras. Some computers have an SD slot
built in so it's very easy to transfer the recordings to your computer for processing.

8. Where do audio samples come from?
From Web sites.
• YouTube (remove video)
• Internet Radio (streaming)
• Radio Plays (google)
• Podcasts (google: EFL podcasts)
• LibriVox (audio books, search by language)
• Creative Commons (free, public domain, search)
Some sources from the Web are free and some are not. Check out the list on the Moodle site under 'Resources'. If you put a
YouTube video into Switch and convert it to an mp3, it strips the video and leaves you with an audio file. The lesson on
Video shows you how to download a YouTube video onto your desktop.

9. Audio Formats
• With Compression (mp3, mp4)
- smaller file size (1/10th)
- lower sound quality
- close to CD quality (192 bits)
- play on mp3 player or computer (iPod)
• Without Compression (wav, aiff)
- larger file size (10 times larger than mp3)
- higher quality
- quality difference not discernible by everyone
- play on CD or DVD player
Use mp3 files for everything unless you need the highest-quality music files. For language learning, mp3 files will work well.

10. File Formats
.mp3 (most popular, files can contain data)
.mp4 (sound & video)
.wav (larger files, best for music, Microsoft)
.aif (larger files, best for music, Apple)
99.99999% of the time, you will use the mp3 format for language learning. The file size is 10 times smaller than a wav file with
exactly the same content!

11. Streaming vs. Hard Drive
Streaming
• file not stored on hard drive
• can listen almost immediately
• requires plug-in (QuickTime, WMP, Real Player)
• can 'choke' on slower network connections
• online radio
Hard Drive
• file stored on hard drive
• can listen after file is completely downloaded
• needs application
• downloading longer on slower network connections
You can have a sound file that is located in the 'cloud', in other words, someplace else on the Web and the sound comes to you over
the Web through streaming. Or the sound file can be on your computer hard drive. There are advantages & disadvantages in both
cases. Cloud-based applications such as Google Docs will only play streaming media.

12. External vs. Internal Player / Plug-in
QuickTime
Real Player
Windows Media Player
You may have to install a plug-in to play audio or video files. All Macintosh computers come with QuickTime already installed. All
Windows computers come with Windows Media Player already installed. Click on the links to find out more about each plug-in.

13. Sampling Rates in KHz
8 KHz phone
11 KHz AM Radio (good for talk)
22 KHz FM Radio (good for talk & music)
44 KHz CD (good for talk & music)
The chart shows different sampling rates and the relative sound quality that you get for each rate. The higher the sampling rate,
the better the sound quality and the bigger the file size. For language learning materials, 22KHz is fine. With Audacity and other
sound recording programs, you can change the sampling rate. Be sure to do this BEFORE you record. You can't increase the
sampling rate after you make the recording.

14. Bit Rates
8-bit
16-bit
DEMO
Another issue when recording is the bit-rate. You only need to know that all your recordings should be 16 bits or higher. The
higher the better. However, some programs can't handle more than 16 bits so for language learning software, stick to 16-bit
recordings. To hear the difference in quality, click on DEMO above. With Audacity and other audio recording software, you can
set the bit rate but you must do this BEFORE you start the recording. You can't improve the bit rate after the recording is made.

15. File Formats - File Sizes
Conversation
Kb - 1 Kb = 1024 bytes (1 letter = 1 byte)
WAV - 999 Kb (CD quality sound, CD player)
MP4 - 238 Kb (sound & video, iPod)
MP3 - 94 Kb (sound, close to CD quality, iPod)
The basic idea is to keep your file sizes as small as possible. The file size for different formats differs greatly. If you click on
Conversation above, a player will appear. Click on Conversation in the player list and you'll hear a short dialog. The same dialog in
different formats varies from 999 Kb in wav format to 94 Kb in mp3 format. The file size is 10 times smaller in mp3 with little
difference in quality! A smaller file size means faster download time, better streaming without 'choking', faster processing speed, less
demand on the computer's CPU.

16. Important Question!
"How much does audio cost in memory, processing speed
and download time?"
10 MB Audio File Download Time
180 sec. 56K modem
60 sec. 750 Kbps DSL
30 sec. 1.5 Mbps DSL
3 sec. 15 Mbps cable modem
Test the speed of your connection at speedtest.net!
The faster your download speed is, the less time it takes to download files or open Web pages. The upload speed is important if you
need to upload files to Facebook, Googe Docs or other servers. The upload speed is always slower than the download speed.

17. Ideal Settings for CALL Projects (voice)
22.050 KHz
16 bit
mp3
Sampling Rate:
Bit Rate:
File Format:
The settings above will give you the best quality and the smallest file size. Audacity and other audio recording programs will let you
adjust the settings but you must do this BEFORE you start the recording.

18. Recording Issues
• Microphones (internal, USB)
• Artifacts
• Popping
• Too far from mic
• Hiss
• Hum
Demo
There are good recordings and there are bad recordings. Bad recordings can hinder a student's progress in listening comprehension
and pronunciation. Bad recordings have artifacts (things that shouldn't be there) such as popping, hissing and humming. To prevent
popping, use a windscreen on the mic or just hold 3 fingers in front of your mouth as the alien is doing in the photo. It's very
important for the speaker to be as close to the microphone as possible without getting too close! For examples of some artifacts,
click on the links above.

19. Recording Issues
• Ambient noise (use sound insulation)
-ventilation
-TV
-phone
-talking computer (announcing time, error)
-people talking, milling about
• Volume level
-adjusted for earphones?
-consistent?
A common problem with recording is background noise. I've seen many interviews for language learning where the speakers are on
a street and the sound of the traffic almost drowns out the speakers. Conversations in a restaurants don't work very well either
because of all the background noise. Also, make sure your volume levels don't go up and down to the point of distraction or pain!

20. Recording Issues
• Background Music
-Too loud?
-Distracting?
-Wrong mood?
-Copyright infringement?
A common problem with recording is background noise. I've seen many interviews for language learning where the speakers are on
a street and the sound of the traffic almost drowns out the speakers. Conversations in a restaurants don't work very well either
because of all the background noise. Also, make sure your volume levels don't go up and down to the point of distraction or pain!

21. Recording & Editing Audio
• Audacity (free, open source, Mac & PC)
• LAME (plug-in used with Audacity to export files as mp3)
• Garage Band (free with Macintosh)
• Media.io (converts audio files to mp3, Web app)
• Sound Recorder (free with PC, only in wma file format)
There are several free programs that let you make digital audio recordings. Some are very sophisticated and some are very basic.
Check the links above to get more info about these applications.

22. Storing Audio Samples Online
www.4shared.com
drive.google.com
soundcloud.com
Check the Moodle site for other cloud storage options. Storing files 'in the Cloud' is the wave of the future and it's happening now. In
the future most storage and applications will be Web-based or 'in the Cloud'. There are advantages & disadvantages. The biggest
disadvantage is that you won't have access to your files if you lose your Internet connection. For this reason, KEEP A COPY ON YOUR
COMPUTER HARD DRIVE! I always use the Coud to keep a copy of my projects. That way, if my computer melts or implodes, I still
have another copy available outside the house.

23. Things to Think About
You can go from HIGH quality to LOWER quality BUT
you can't go from LOW to HIGHER quality SO start with
HIGH quality!!!!!!!!!
Sample Recorded at: 5.56 KHz, 8 bits (low quality, low settings)
Modified to: 44.10 KHz, 16 bits (low quality, high settings)
DEMO
“Jingle bells, jingle bells
Jingle all the way
Oh, what fun it is to ride
In a brand new Chevrolet”
Click on DEMO above to hear the audio samples. I made a low-quality (5.56 KHz, 8 bits) recording and then saved it at a
higher sample rate and bit rate. Does the second recording sound any better?

24. Things to Think About
Is the style of language appropriate for the target group?
Slang
As far as content goes, there are several things that you should think about when selecting material for your students. For
example, slang may be appropriate or it may not be, depending on what your instructional objectives are.

25. Things to Think About
Is the style of language appropriate for the target group?
Derogatory or Insulting Language
"Ye foul-smellin', grog-shy, lice-infested sea snake...garr!"

26. Things to Think About
Is the style of language appropriate for the target group?
Obscene Language
#%&!

27. Things to Think About
Is the style of language appropriate for the target group?
Formal vs. Informal
Sup,dude?
Personnel

28. Things to Think About
Is the style of language appropriate for the target group?
LSP (Language for Specific Purposes)
Business
Science & Engineering
Health and Social Services
Law Enforcement
Politics
Language for specific purposes has unique vocabularies and may use common words with different meanings. For example...

29. Things to Think About
Is the style of language appropriate for the target group?
LSP (Language for Specific Purposes)
bat
... a 'bat' in biology is different from a 'bat' in baseball.

30. Things to Think About
Is the style of language appropriate for the target group?
Standard vs. Non-Standard
Correct Grammar: “If it isn't broken, don't fix it!”
Sometimes non-standard or incorrect grammar is used for emphasis or for cultural reasons. Even though the expression above
has incorrect grammar, this is how the expression is always used for emphasis.

31. Things to Think About
Is the style of language appropriate for the target group?
Age Level
"See the cat. The cat has a hat."
Adult learners may have the same language level as a 2-year-old native speaker but the material for a 2-year-old native speaker is
probably not going to interest adult learners. What other options do you have, if you're teaching beginning adult learners?

32. Things to Think About
Is the focal point clear?
What's this conversation about?
(You may want to take notes.)
Click on the link above to hear a conversation. Does this recording have any instructional value? Why or why not?

33. Things to Think About
Is the style of language appropriate for the target group?
Out-moded
Does the language sound as if it comes out of an old movie? Maybe you ARE watching an old movie with your students. Words such
as golly, fellas and swell were used in the 1940's but are considered old fashioned today. The word that's is still OK though.

34. Things to Think About
Is the style of language appropriate for the target group?
Regional Accents
Maine Accent
(New England)
North Carolina Accent
(Southeast)
If the material you're using has regional accents, the accents might be a distraction or make the material harder for your students to
process. In the English version of the movie 'Terminator', Arnold Schwarzenegger speaks with his own voice. His native language is
German but his German has a distinct south Austrian accent. Although Arnold could dub his own voice in the German version of the
movie, another voice actor with a standard German accent did the job because Arnold's regional accent would have been a distraction.
Imagine the Terminator in English with a Bronx accent. Click on the images to hear the different accents.

35. Things to Think About
Is the style of language appropriate for the target group?
National Accents
Do your instructional materials represent the different national accents? Will you teach your students to prefer one accent over another? How will you explain
the different accents and even different words (flat vs. apartment or lift vs. elevator)?