A version of this paper was first presented at a plenary session of the Canadian CALL conference in Guelph, 1989. At that time computer sound cards and speech recognition software existed but were expensive and fairly primitive by present standards.
A speaker uses breath pulses, modulated by the flexible cavities of the vocal tract, to produce cyclical air pressure variations. These spread in waves to where they may encounter a listener and produce minute but infinitely variable distortions of the eardrum. A writer moves a pen or hammers a key to produce an irregular darkening of a white surface, which may then be put
in front of a reader in enough light to form an image on the retina.
These are essentially analogue processes.
Language, however, imposes a digital system on the analogue facts. Noises are assigned unequivocally to phonemes, shapes to graphemes, and sequences of these to words and sentences.
Aided by considerable processing input by the receiver, sentences
become meanings or messages. Sometimes, of course, the data being
received is contradictory or indeterminate; the signal is corrupted
and the system has to go into repair mode: "Sorry, what was
that?" or "I can't read your sister's handwriting."
The title of this paper is a truism, something that linguists have
known for a long time, though they may not have expressed it in
those words. It is, after all, the basis of the whole of phonology.
It doesn't matter, in a word like lamb whether I use a clear l, a dark l or anything in between. Because I am speaking English and you are listening in English, you assign the noise I am making to the /l/ phoneme. If I say ram you assign the first noise of that word to the /r/ phoneme. But if you are listening in Japanese, you may find that more difficult to do. Listening is digital, but the base is different in different languages.
Think how easy it is to spot the exact moment wo man auf einer anderen Sprache zu sprechen anfaengt, und auch genau wo you start to speak the first language again. Funnily enough this becomes even easier when one of the languages in the pair is completely unfamiliar. If I start in English lewkoo
gamlang phuud pasaa thai, khun mai khawchai leui theung wela I
start speaking English again. I imagine you found it quite easy
to identify the crossover points, even without knowing what was
going on in the middle. There is no gradual blending. I am speaking
English or I am not speaking English.
| "Yes, that was definitely /ɪ/ rather than /i:/"; | |
| or | "Your /y/ was insufficiently rounded." |
This is where a very simple computer program can help. The computer can set the learner a task, e.g., to read aloud a sentence or answer a question, while the assessor is not told which one of several possible tasks has been set. Thus the question in the assessor's mind is not "Was that a good attempt to say the word ship?" but rather "Was the candidate trying to say ship or sheep?"
To test single phoneme contrasts, one makes the computer print out a task sheet for the candidate like this:
Read these sentences aloud.
One hardly ever sees any whales nowadays.
The pilots were responsible for many shipwrecks.
You've got to heat it.
Be careful! That heel's dangerous.
I was surprised when he gave me the rice.
The rats needed more room to breed.(BABAAB)
Each is randomly generated and the actual sentences
will vary from candidate to candidate. Meanwhile the assessor gets a check
sheet like this:
One hardly ever sees any (A) veils nowadays.
(B) whales
The (A) pilots were responsible for many...
(B) pirates
You've got to (A) eat it.
(B) heat
Be careful! That (A) heel's dangerous.
(B) hill's
I was surprised when he gave me the (A) rice.
(B) lice.
The rats need more room to (A) breathe.
(B) breed.
The assessor listens to the sentences, checks A or
B for each, and then compares the list with what is printed at
the bottom of the candidate's sheet In effect what we are doing
here is to have the candidate give the assessor a listening test.
We are certainly making the assessor behave more like a listener
dealing digitally with the question "What is the candidate
trying to tell me?" rather than like a judge dealing in an
analogue way with the question "How well can the candidate
make that sound?"
There are still problems. The tasks are not necessarily
of equal difficulty, and most candidates who get the word breed
can consider themselves "luckier" than those who
get breathe. This may need to be adjusted by having certain
contrasts turn up several times, with the harder option more frequent,
though not so frequent that it makes the word predictable. If
the test is prepared for diverse language backgrounds, a number
of items will present no difficulty to particular learners. One
might eventually, when records have been amassed, be able to make
the test sensitive to specific languages, so that a test sheet
for a Japanese learner would contain more r/l contrasts and no
s/z contrasts, for instance.
For example:
(Read this sentence as if you are talking to (A) Miss Jenkins / (B) a different person)
This is my colleague, Miss Jenkins.
(Say this sentence as an answer to the question (A)
"Was he a clever student?' or (B)"Wasn't he rather a bad student?")
He was an extremely clever student.
You need some ingenuity to devise items that cover
a wide range of stress and intonation features, and there are
problems with the metalanguage used to describe the tasks. However,
it may still be worth including some items of this kind if students
have been suitably prepared. For the time being we are waiting
for an opportunity to carry out trials to see
whether the technique is reliable and economical.
The library has thousands of books, but there
isn't one of them that I really want to read.
A meaningless fragment, just a syllable or so, was
picked out of each sentence, and then the sentence was extended
outwards in both directions four times in steps of half a second.
At the sixth step subjects heard the full sentence.
Subjects were asked to write down each fragment they beard in any way they could represent it. The object was to see at which point they stopped writing nonsense syllables and started writing words that made sense. There were twenty volunteers, ten of whom were native speakers and ten were overseas students of intermediate or better standard in English. They were divided into two sub-groups, one hearing the sentences in a well-established context and the other hearing the sentences "cold." All the tests were carried out individually, and subjects could ask for as many repetitions of each fragment as they wanted.
Several rather unexpected findings came out of this
little experiment One was that, although the penny dropped more
or less as predicted for the native speakers, most of whom could
predict the whole sentence by the third or fourth fragment, most
of the foreign learners never made sense of the utterances and
produced highly garbled transcriptions of them. The other interesting
point was that knowledge of context seemed to make no measurable
difference for either native or non-native speakers. We are still
trying to work out the implications of that finding.
I wouldn't do that it I were you.
and see
Only word 4 occurred, but all the distractors were sound sequences which had occurred in the spoken sentence though not as meaningful units. If the sentence had been a meaningless blur of sound, then they had "heard" all four words, and it was only if they had succeeded in "writing out" the complete sentence in their minds that they could reliably spot the real word among the distractors.
For some reason this testing technique seemed to fall out of favour, and it has not been used to my knowledge since 1969. 1 have often wondered why. I suspect it is because the technique had low face validity, and that candidates suspected a trap of some kind and resented the form of test. This happened to some extent when I used similar types of test in entrance examinations in Turkey. The test itself performed magnificently well as far as the statistics were concerned, but it was unpopular. However, I still feel that the activity supplies reliable indications of the listening skill and might even have applications in training learners to listen. As long as this is just a hunch, it needs to be examined, and I have several students working on this kind of activity.
The public forms of this test that were used in the '60s all presented isolated sentences out of context. One thing I am keen to investigate is how the test is affected by being carried out with sentences which form a coherent text. One project was carried out in 1989 by a Bristol student on Omani schoolchildren, using texts taken from a local textbook. Preliminary results here suggest that familiarity with content (falling short of recent close study of the text) may have very little effect on performance. In a follow up study conducted by Eiman Marafi of Kuwait, the learning effect of having to listen for specific types of function words has been examined; does an expectation that the key word may be there or can, for instance, affect the way that learners listen for weak forms? This work will be reported on by the end of 1996.
Meanwhile the computer in the context of my own work is already turning the whole area of pronunciation and phonetics into a more experimental subject, allowing my students to look at sound as well as hear it, and to get rid of some of their preconceptions about, for instance, sounds and spellings, even at the simple level of discovering that doubled letters in spelling are not double articulations. This is part of a general service that computers in their slave role can provide for language learners, namely the opportunity for learners (not just teachers) to experiment. Expressed as a slogan, it puts the trial back into trial-and-error.
Page prepared by John Higgins, published as an HTML document on 17 September 1996, revised April, 2008.
Visitors since 1 May 2008: