23. Advanced speech analysis tools II: Praat and more
Judging
from mentions spotted on the Internet, Praat (Dutch for 'talk'), created by
Paul Boersma and David Weenink of the Institute of Phonetic Sciences, University
of Amsterdam, is currently among the most popular of free, downloadable speech
analysis software packages. It is used in ESL courses for relatively basic functions,
like making waveforms for students to compare their pronunciation against that
of a native-speaker model. It is used in introductory phonetics classes for
spectrogram making, pitch tracks, and other functions we have been using WASP
for. And it is used for more complex kinds of analysis by those who are at an
advanced level in their study of phonetics and know a bit about computer programming
and 'script' writing. So Praat is highly flexible; you can use it to good advantage
whatever your current level is.
Praat can be downloaded from this page; click
on 'Windows' (unless you use some other operating system; then click on the
appropriate link):
http://www.fon.hum.uva.nl/praat/
One big advantage of Praat is it includes a clear
and very detailed user's manual to help you learn how to use Praat's many functions.
After installing Praat, click on 'Help', and start going through the user's
manual, page by page, to learn what you can do with Praat, and how to do it.
In addition, Sidney Wood, formerly of Lund University, Sweden, has a helpful
introductory tutorial on the use of Praat on his Website. The URL is:
https://swphonetics.com
On the Praat homepage, you will also find a link
to e-mail address of Prof. Pascal
van Lieshout of the University of Toronto (or you can use this link), who
has written a short tutorial for the Praat program. Just send him a note saying,
'Could you please send me a copy of your Praat tutorial?' and he will send you
a pdf (Acrobat) file of this very clear and helpful tutorial. Although the tutorial
was specifically written for clinicians in the field of communication disorders,
it is a very accessible introduction for the general user as well.
Here
is a list of just a few of the things you can do with Praat, to get you started:
you can generate waveforms, wide and narrow band spectrograms, and pitch tracks
(as with WASP); you can play a recorded sound in reverse; you can further process
a speech signal by filtering it (as with SFS: high-pass, low-pass, band-pass,
band-stop); you can also enhance certain frequency regions; segment and label
words, syllables, or individual phonemes; show an intensity contour; put your
work in graphic form ('draw a plot') for printing; extract individual sounds
for further analysis; and measure voice onset time (VOT). If you are interested
in phonology, there are Optimality Theory tutorials and tools to make OT tableaux
(look these terms up, if you are interested). You can even generate an animated
outline model of a vocal tract making a particular sound! Praat's possibilities
are seemingly endless.
As with any new tool, it will take an investment
of time and effort to learn how to make Praat do what you want it to do; but
it is well worth it. Once you know how to use some of Praat's functions, you
will have a very powerful set of learning and analysis tools at your disposal
that can help bring you up to the next level in your study of phonetics. Don't
rush! Learn a bit at a time, but keep at it every day for a while. You will
feel a tremendous sense of accomplishment with each new skill you learn!
In these two pages, we have introduced only two
speech analysis software packages, SFS and Praat. There are many others available
for you to try. Here is a partial list of these programs, with links to their
introductory or download pages. Visit each site, try out the program offered
if it appeals to you, and see what it can do. Decide for yourself which one
or ones are best suited to your particular needs.
WaveSurfer: An
open source tool for sound visualization and manipulation; by Kåre Sjölander
and Jonas Beskow of KTH (the Royal Institute of Technology) in Stockholm, Sweden
http://www.speech.kth.se/wavesurfer/
SIL Speech Analysis software
applications
http://www.sil.org/computing/speechtools/
Mark Huckvale and
UCL offer a number of interesting speech analysis programs besides WASP and
SFS that you can explore:
(1) SFS/Browse:
Drag and drop audio files in a range of formats onto the display to see
and hear their contents.
http://www.phon.ucl.ac.uk/resource/sfs/browse/
(2) UCL Enhance:
A program for the enhancement of the intelligibility of speech recordings. The
program incorporates a number of standard techniques for manipulating the overall
amplitude of the signal and for the removal of steady-state additive noise.
http://www.phon.ucl.ac.uk/resource/sfs/enhance.htm
(3) SFS/ESYNTH:
A program designed to explain the harmonic analysis and synthesis of signals.
With ESynth you can create signals by adding together individual sinusoidal
waveforms (sinewaves) and study the resulting waveform and spectrum. You can
also perform an analysis of an input waveform, to see how a given sound can
be represented in terms of a sum of sinewaves.
http://www.phon.ucl.ac.uk/resource/sfs/esynth.htm
(4) SFS/ESYSTEM:
See the effect of simple systems on a range of simple signals. You can generate
simple signals such as sinewaves, pulses, pulse trains, sawtooth and noise;
you can pass them though systems such as an amplifier, a resonator, a low-pass,
high-pass or band-pass filter, or a vocal tract model.
http://www.phon.ucl.ac.uk/resource/sfs/esystem/
(5) SFS/RTSPECT Version
2.1: With this program you can monitor the waveform and spectral
shape of sounds being played into the computer's microphone or line input ports.
http://www.phon.ucl.ac.uk/resource/sfs/rtspect/
Here is a whole
list of speech synthesis and analysis software, with links (some of which may
be dead):
http://linux-sound.org/speech.html
My personal preferences: I use WASP for simple
needs, like waveforms and spectrograms, because it is small, loads quickly,
and is uncomplicated by lots of other features. I sometimes use SFS for features
I have come to depend on it for, for some reason or other. But if I were to
pick just one all-purpose program, it would definitely be Praat. It is not difficult
to use, it has just about every conceivable function you will have occasion
to use, and the help files are clear and truly helpful. The authors offer good
support for their program. And it's free!
We have learned about Daniel Jones's cardinal
vowels in chapter 9 of Ladefoged's Course. From the next page,
you will be able to link to recordings of the cardinal vowels made by Daniel
Jones himself. The site that offers the recordings is based in the Netherlands,
so don't panic when you discover that parts of the site are written in Dutch.
You will be able to find your way around just fine!
Next: Daniel Jones's cardinal vowels
(before this page is ready,
you can link directly to the cardinal vowels page by clicking here;
Peter Ladefoged has similar recordings on his site here)
on to next page back index I index II home