It’s been a while since I’ve strayed into the Mystic side of Linguistic Mystic. This evening, while Wikipedia-Surfing, I stumbled upon an interesting reported phenomenon: Electronic Voice Phenomena (or EVP). Since I spend a great deal of my free time looking at voices and how speech works, I was interested to see what a bit of phonetic analysis would do to some of the examples that its proponents have given.

Disclaimer

EVP is not a well-studied phenomenon and there is little (if any) scientific evidence in favor of its existence. This post should not be construed as an endorsement of this phenomenon or an assertion of its reality. I try to keep an open mind on such things, but I’m doing this analysis for my own interest (if nothing else, “paraphonetics” is a cool sounding field name), not for any legitimate, scholarly purpose. Take this post (and, if you’d like, the phenomenon itself) with a grain of scientific salt.

What is EVP?

In the words of the American Association of Electronic Voice Phenomena’s FAQ page on EVP:

Electronic Voice Phenomena (EVP) is the term traditionally used to describe unexpected sounds or voices sometimes found on recording media. EVP initially involved audio tape recorders, but in later years, virtually any recording medium became a vehicle for phenomena. The term Instrumental TransCommunication (ITC) came into being to describe these expanded modes of audio- and video-format communication. Other acronyms used in the literature include Electronic Disturbance Phenomena (EDP) and Trans-Dimensional Communication (TDC).

For a more two-sided (and skeptical) discussion and other resources, I encourage you to visit the Wikipedia page on EVP.

Long story short, EVP are anomalous voices that show up in recordings, often claimed to come from the dead. These voices are reported to be phrases, words, or even dialogues with a living speaker.

Praat and the Paranormal

When I first read about this, I decided to try and find some samples of this phenomenon and run them through Praat, a Phonetic Analysis program. Luckily, the AAEVP provides a number of examples on their site. The one I’ll be analyzing today comes from Vicki Talbott’s Examples, and purports to feature a discussion between her and her son who had recently died, discussing the proper pronunciation of the word “evidentiary”. I encourage you to read her explanation (the last example on her page) and listen to the file a few times before I proceed.

As you can hear, her voice is quite clear (albeit recorded), but the other voice is nearly incomprehensible if you’re not sure what you’re looking for. However, I was curious just how much of the data I’d expect to find in speech would be there, and how much is my brain filling in the blanks. Let’s look a little more closely at the acoustics of the voices.

What’s in a voice?

We hear patterns of sound based on the emphasis and damping of certain parts of the sound spectrum. The vibration of our vocal folds is fairly constant (excepting the occaisional pitch or voicing change), but we’re almost constantly moving our mouths and tongue. Just as your voice changes when you put your mouth to a flexible tube and talk while bending the tube, the sound of your vocal folds vibrating is changed by the position of your tongue, lips, and velum in your mouth and throat. Different vowel sounds are created by modifying the shape of the mouth, which in turn modifies the sound escaping your mouth to be heard by others. This is called the Source-Filter Model of Speech Production.

So, when we hear another person make a sound, say, the vowel ‘i’ (as in feet), we’re analyzing which parts of the sound from their vocal folds are being damped (supressed) and which parts resonate (are stronger). For example, in the vowel /i/, there are strong bands of resonating sound (called ‘formants’) around (roughly) 250hz, 2500hz, and 3000hz. We hear these particular parts of the spectrum being emphasized, and interpret them as somebody making an /i/.

These formants (along with the gaps between them and some other sounds) are what we’re listening for in speech. In clear speech, the formants are well defined and strong, but in distorted or mumbled speech, they’re very tough to pick out, both by computer and with our ears.

Evidentiary evidence

So, for comparison, I’ve recorded a file of myself saying “evidentiary”. Give it a listen, if you’d like.

When I open this file in Praat, it shows me a part of the spectrum (0-5000hz). On that Spectrogram, there are darker parts and lighter parts. The darker parts show the formants (the resonating parts of the spectrum), and the lighter parts show the damped portions. I’ve also had Praat draw red dots on the formants, to make them a bit more distinct. Here’s a screenshot of the spectrogram for my “evidentiary”, labeled with English on top, and IPA on the bottom:

As you can see, the heights and separation between the formants (black parts with red dotted lines) are distinctly different for the initial “e” and the “ia” in the middle. If they weren’t, the vowels would just sound the same. Similarly, there are other trademark signs of speech sounds. The ’sh’ sound (ti in English) shows up with a burst of noise around 3000-7000hz (as one would expect), and the ‘n’ makes everything a bit damped and quieter (as do all nasal sounds). All the formants are well defined, and Praat doesn’t have much trouble finding them and sticking to them.

Now, let’s look at a spectrogram of Talbott’s recording, annotated the same way, with red dot formants, and using her transcriptions from the diagram at the bottom of her site:

Of course, the spacing is different, and based on the white streaks around 200hz and 3500hz, it looks like she’s done some filtering to isolate these sounds. The interesting part about this is that there aren’t any well defined formants. Praat is great at finding formants in good files, but it’s also quite adept at finding them in bakcground noise if there’s not any good speech in a given file. As you can see, there are three pretty constant bands of red dots going across the entire spectrogram, with the same amount of variation in the silence as in the “spoken” portions. Although Praat thinks they’re formants, when compared to the relatively sharp black lines in my version, it looks like it’s just finding whatever pattern it can in the noise.

It doesn’t seem like there’s much of anything in the way of clear formants or expected voice patterns. The noise for the ’sh’ is missing from ‘ti’, the ‘n’ doesn’t seem to affect much, and the formant patterns over the two different /i/’s don’t really match (as they did in mine). Over all, there’s not a lot here to latch on to, and, as you likely noticed when listening to it, it’s by no means obvious what’s being said. Most of the auditory cues we use to pick out meaningful speech are absent acoustically, yet, with a few repetitions, we can usually convince ourselves that we’re hearing speech here.

What does it all mean?

Based on what I see here (in this one example), it seems like many of the fundamental characteristics of human speech are missing in the second, purportedly paranormal voice. I suspect that this is what makes it nearly incomprehensible without coaching.

What does that mean for EVP? Well, nothing, really, because my study here isn’t particularly scientific. Just because a phledgling phonetician doesn’t see speech through one method of analysis doesn’t mean it’s not there. Also, I can’t be sure what sorts of filters were used that might have changed the sound quality. I’m not sure what results a different file would yield.

However, even if this were a perfect analysis, all that I’m proving here is that it’s actually similar to normal human speech. The EVP people will still defend their assertions, and the skeptics will still have their objections to their claims (and methodology, and other such things).

The difficulty with Paraphonetics

The other relevant question is whether such study really matters at all. To the people who believe in EVP, the clarity (or closeness to normal human speech) may not be particularly relevant.

Phonetics is a very exact sort of science, but anything to do with the paranormal is extremely subjective. We can scientifically measure things all day long, but in the end, these sorts of phenomena depend on the interpretation of the listener. Perhaps Vicki Talbott heard “evidentiality” in that noise because of her previous question (using context to make sense of inaudible portions of a “conversation”). Perhaps the noise just coincidentally sounds enough like “evidentiality” to trip the human brain’s speech analysis functions. However, as is the case with all paranormal claims, one can never prove the negative (we can’t prove completely that nothing paranormal occurred in this tape). You’re welcome to believe whatever you’d like on the subject.

Regardless, next time you go out ghost-hunting, you might want to grab a copy of Praat. It can never hurt, and at the very least, Praat can help you find some phantom formants in the background noise. It might not sound scary to you, but in the middle of a research project, they can be downright terrifying.

(I lied, I’m getting another post in before I leave.)

Today on the bus there was a radio ad playing for some sort of storage company. This ad was an “interaction” between a female narrator and a male narrator, who, for some reason, was speaking mostly in Pig Latin.

Ackground-bay

For those unfamiliar with it, Pig Latin is an spoken English word game in which one removes the first consonant (or consonant cluster) in a word and places it at the end of the word, followed by the vowel sound /ei/ (as in “hey”, “play” or “may”). So, dog becomes “og-day”, blog becomes “og-blay”, and grammaticalization becomes ‘ammaticalization-gray’.

It’s relatively common, and has entered the popular domain in a number of places. Google (oogle-gay?) is available in pig latin, and the “ixnay on the ______” construction is fairly common (meaning “Don’t talk about/do ______”). Interestingly, there are similar (but not identical) language games played in other languages. Wikipedia has a list of some of these games which has some very interesting examples.

Anks-tay or anks-thay?

So, on this radio ad, at the very end of the ad, the female narrator said “Thanks”, and the male corrected her to “anks-tay”.

This is interesting because generally, the consonant is kept the same in pig latin, just moved to the back of the word. So, I’d expect it to be “anks-thay”, with a θ (the sound in “thistle”). This got me to thinking, why would this happen?

ut-whay oes-day onology-phay ave-hay u-tay u-day ith-way it-ay

Phonology, as I’ve mentioned before, is the study of sound systems in a language. Every language has a system of rules which dictate which clusters of sounds and sounds are valid, and which aren’t. For this reason, “lomin” sounds like it could be an English word, but “ngostla” doesn’t. If you try and pronounce something and have lots of trouble, chances are, it’s violating a phonotactic rule of your language.

So, what’s wrong with “anksthay”? Well, I tried pronouncing it. Even with my training in pronouncing strange things, it’s a bit troublesome to go from a k to an s to a θ without any vowels to rest. Since each sound is made in a different place in the mouth (the velum in the back for the K, the Alveolar ridge for the S, and with the tongue between the teeth for the θ), you have to do a lot of moving without any rest.

Compare this to “ankstay”. We have no problem with this (it’s very similar to “angst” an accepted English word) because the “st” cluster is pretty easy to make. To make an S, you bring your tongue up to the alveolar ridge (the bony ridge of the roof of your mouth, just behind the teeth) so it’s just far enough away to cause friction in the air. To make a T, you put the tongue in the same place, except you make a complete closure. To make an “st” cluster, your tongue stays in the same place, it just moves upwards to change the S to a T.

For English speakers, “kst” is a much easier cluster to handle than “ksth”. There may be a phonological or phonotactic rule to explain it, but I’m not sure what that rule would be offhand. However, if we just look at the clusters that exist in the language, we can figure out what’s allowed and what isn’t, and suddenly, it all becomes clear.

Languages games like Pig Latin may not be serious in use, but studying how people use language when playing them can reveal a great deal about the phonology and phonotactics of the language in question.

See, even the most serious linguist has a place in their life for fun and games.

As a linguist, you find yourself using the International Phonetic Alphabet (IPA) incredibly frequently. Some of the characters are easy enough to use without any special work (ŋ, ə). However, to get the more cool/obscure characters and diacritics, or to stack diacritics (placing, for instance, a tone marking above a nasal marking), you need special fonts, layouts and setup. In this post, I’m going to explain, as simply as possible, how to go about finding the files and setting this up, all without paying a dime for specialty software.

Getting the fonts and layout

The beauty of this method is that it uses software built into Mac OS X, and that you can use IPA fonts in any application that supports Unicode (translation: lots of them), not just specific programs. You also don’t need to install a separate program to clutter up your computer, just a few free fonts and a keyboard layout. So, here’s your freeware shopping list:

Necessary files:
1. Charis SIL IPA Font - The best free IPA font out there (in my opinion) because it has bold, italic, and all sorts of other characters outside of IPA. The download link is around halfway down the page, grab the file with “(Windows, Macintosh and Linux)” next to it. Thanks to the Summer Institute of Linguistics, it’s completely free!
2. The IPA-SIL Keyboard Layout for OS X - The only IPA Keyboard out there for OS X. It’s truly a wonderful thing, and completely free, thanks again to SIL. It says that it’s specific to Doulos SIL, but that’s a blatant lie, as I use it all the time with Charis. (I’d recommend the Version 0.6 Alpha on that page, not the more recent one. Although the more recent one works, it’s just a bit more complex. The instructions here are for the older, alpha version.)

Optional Files
Doulos SIL - A differently styled IPA font from SIL, missing the bold and italic forms that Charis has. Still free :)
SILIPA93 Fonts - These are desperately outdated, but occasionally necessary when reading other people’s old IPA.

Download at least the CharisSIL and the Keyboard layout, save them to your desktop (or a location of your choosing), and then proceed to the next step.

Power User’s Summary: Download CharisSIL and IPA-SIL keyboard Layout from the above links

Installing the font

Now, double-click the CharisSIL(version).zip file that you saved to your desktop. It’ll unzip into a similarly named folder on your desktop. Take the CharisSILfontdocumentation.pdf file and move it to a safe place, it’s a handy guide to have around, and feel free to take a look at the readme and license files in the folder.

Now, if you want to install this font for yourself and every other user on your computer, place the four font files from the folder (CharisSILB.ttf, CharisSILBI.ttf, CharisSILI.ttf, CharisSILR.ttf) along with any other fonts you’re installing into the /Library/Fonts folder. You’ll need to give an administrator password to install them into that folder.

To install for yourself alone, do the same as above, except by copying things into /Users/yourname/Library/Fonts. No admin access needed for this route.

Power User’s Summary: Install the font files in either /Library/Fonts or /Users/you/Library/Fonts

Installing the layout

Double click “IPA-SIL keyboard(version).dmg” on your desktop. Now click the newly opened “IPA-SIL Keyboard” Disk Image on the desktop and examine the contents.

The very first step is to save IPA-SIL.pdf! In fact, frame it. Wallpaper your wall with copies of it. Get a version tattooed on your chest. Just make sure you have it. Without this, you’ll have trouble figuring out exactly which keypresses result in which characters, and this method won’t work very well at all.

Now, drag BOTH IPA-SIL.icns and IPA-SIL.keylayout into either /Library/Keyboard Layouts or /Users/yourname/Library/Keyboard Layouts. As before, you’ll need Admin access to install in /Library/Keyboard Layouts. Also, you might have to create the …/yourname/Library/Keyboard Layouts folder if you’re installing for yourself only.

Once you’ve placed the files in the right folder, restart your computer.

Power User’s Summary: Save IPA-SIL.pdf. Drag BOTH IPA-SIL.icns and IPA-SIL.keylayout into either /Library/Keyboard Layouts or /Users/you/Library/Keyboard Layouts. Restart.

Final Configuration

Once you’ve restarted, go to the System Preferences Application. Click the ‘International’ preference pane, then, click the “Input Menu” tab inside the International Pane, and you’ll be presented with a window like this:

In this window, make sure and select “Keyboard Viewer” (to see what symbols are where at a glance), “Allow a different input source for each document”, and “Show input menu in menu bar”. Also, feel free to change the shortcut to switch input methods to make things faster for you down the road.

Now, use the scroll bar to scroll through the list of options until you finally see “IPA-SIL”, and select it. It’s right below the Eskimo languages. See below:

Now that you’ve done that, you should have a little American flag (which regrettably cannot be changed, even if you’re using a US keyboard outside of the US) in your menu bar. Congratulations! You’re now set up to use the IPA on your mac.

hɛloʊ wɜɹld!

To test it out, fire up any text editor (TextEdit, NeoOffice, MS Word, or my personal favorite, Mellel) and open a document. Be very sure to select Charis SIL for your font in the document.

Now, click the little menu in the menubar and select IPA-SIL:

Start typing and you’ll find yourself typing IPA symbols! You’ll slowly learn the reasonably intuitive set of keypresses (e.g: Shift+N = Angma, Shift+R = Alveolar Tap), and soon, you’ll be typing in IPA nearly effortlessly in nearly any application. You can even IM your linguist friends in IPA if they have the font as well.

The best part? Thanks to these free and open source fonts and layouts, you’ll never need to write a Word macro again on OS X. oʊ, wəɾə wʌndɛrfl wɜɹld!

EDIT: I’ve heard that sometimes, Word doesn’t play nicely with this sort of input method. I’d highly recommend that if you have troubles, you try using TextEdit (built in), Mellel, or the free Office suite for OS X, NeoOffice.

At the very least, you should be able to copy/paste your IPA text into a word document, or hopefully even make the switch entirely to a better word processor. Although MS Word may be the most well known word processor, it’s far from being the best, and I highly encourage you to check out all the options.