The document discusses human language processing and psycholinguistics. It covers topics like speech perception and comprehension, lexical access and word recognition, and models of how language is processed both bottom-up and top-down in the brain. Experimental techniques are described that study how quickly words are accessed based on factors like frequency, semantic priming, and irregular spelling.

1. THE HUMAN MIND AT
WORK: HUMAN
LANGUAGE
PROCESSING

2.  Psycholinguistics is the area of linguistics that is
concerned with linguistic performance – how we use our
linguistic competence – in speech (or sign) production and
comprehension. The human brain is able not only to
acquire and store the mental lexicon and grammar, but
also to access that linguistic storehouse to speak and
understand language in real time.
 When we speak, we access our lexicon to find the words,
and we use the rules of grammar to construct novel
sentences and to produce the sounds that express the
message we wish to convey. When we listen to speech
and understand what is being said, we also access the
lexicon and grammar to assign a structure and meaning to
the sounds we hear.

3. Speaking and comprehending speech can be viewed as a
SPEECH CHAIN, a kind of “brain-to-brain” linking, as shown
below:
Physiologic Physiologic
Linguistic Acoustic Linguistic
al al
Level Level Level
level level

4. THE SPEECH SIGNAL
 Acoustic phonetics is concerned with speech
sounds, all of which can be heard by the normal
human ear.
When we push air out of the lungs through the
glottis, it causes the vocal cords to vibrate; this
vibration in turn produces pulses of air that escape
through the mouth (or sometimes the nose).
These pulses are actually small variations in the
air pressure caused by the wavelike motion of air
molecules.

5. The sounds we produce can be described in
terms of how fast the variations of the air
pressure occur. This determines the
fundamental frequency of the sounds and
is perceived by the hearer as pitch. We can
also describe the magnitude, or intensity, of
the variations, which determines the
loudness of the sound.

6. An important tool in acoustic research is a
computer program that decomposes the
speech signal into its frequency
components. When speech is fed into a
computer (from a microphone or a
recording), an image of the speech signal is
displayed. The patterns produced are called
SPECTOGRAMS or, more vividly,
VOICEPRINTS.

7. •Spectogram also
shows formants
•concentration of
acoustic energy
•Group of
overtones
corresponding
resonating
frequency of the air
in the vocal tract

8. SPEECH PERCEPTION AND
COMPREHENSION
A central problem of speech perception is to
explain how listeners carve up the continuous
speech signal into meaningful units referred as
“segmentation problem”. Another question is,
how does the listener manage to recognize
speech sounds when they occur in different
contexts and when they are spoken by
different people? This is referred to as the
“lack of invariance problem”.

9. In addressing the latter problem, experimental
results show that the listeners can calibrate their
perceptions to control for differences in the size
and shape of the vocal tract of the speaker.
Similarly, listeners adjust how they interpret timing
information in the speech signal as a function of
how quickly the speaker is talking. These
normalization procedures enable the listener to
understand a [d] as a [d] regardless of the
speaker or the speech rate as we might expect,
the units we perceive depend on the language we
know.

10. English can perceive the
ex.
difference between [l] and [r]
because these phones represent
distinct phonemes in the language.
Speakers of Japanese have great
difficulty in differentiating the two
because they are allophones of
one phoneme in their language.

11. Returning to the segmentation problem,
spoken words are seldom surrounded by
boundaries such as pauses. Nevertheless,
words are obviously units of perception.
The spaces between them in writing
support this view. How do we find the words
in the speech stream?

12. A sniggle blick is
procking a slar.

13.  You would still be unable to assign a meaning to the
sounds, because the meaning of a sentence relies
mainly on the meaning of its words, and the only
English lexical items in this string are the morphemes
a, is and –ing.
 The sentence lacks any English content words.
You can decide that the sentence has no meaning
only if you attempt (unconsciously and consciously) to
search your mental lexicon for the phonological
strings you decide are possible words.
 Finding that there are no entries for sniggle, blick,
prock and slar, you can conclude that the sentence
contains nonsense strings. The segmentation and
search of these “words” relies on knowing the
grammatical morphemes and syntax.

14. The cat
chased the rat

15. a similar lexical look-up process would lead you
to conclude that an event concerning a cat, a rat,
and the activity of chasing had occurred.
You could only know this only by segmenting the
words in the continuous speech signal, analyzing
them into their phonological word units, and
matching these units to similar strings stored in
your lexicon, which also includes the meanings
attached to these phonological representations.
(This still would not enable you to understand
who chased whom, because that requires
syntactic analysis).

16. 1. Over lunch, your friend tells you a story
about a recent holiday, which was a
disaster. You listen with interest and
interject at appropriate moments, maybe to
express surprise or sympathy.
2. That evening, another friend calls to invite
you to a party at her house the following
Saturday. As you’ve never been to her
house before, she gives you directions. You
listen carefully and make notes

17. BOTTOM-UP AND TOP-DOWN MODELS
Top down processes proceed from semantic and
syntactic information to the lexical information
gained from the sensory input. Through use of
such higher-level information, we can try to predict
what is to follow in the signal.
For example, upon hearing the determiner the,
the speaker begins constructing an NP and
expects that the next word could be a noun, as in
the boy.
In this instance the knowledge of phrase structure
would be the source of information.

18. Bottom-up processing moves step-by-step
from the incoming acoustic (or visual)
signal, to phonemes, morphemes, words
and phrases, and ultimately to semantic
interpretation. Each step of building toward
a meaning is based on the sensory data
and accompanying lexical information.
According to this model the speaker
waits until hearing the and boy before
constructing an NP, and then waits for the
next word, and so on.

19. LEXICAL ACCESS AND WORD
RECOGNITION
Psycholinguists have conducted a
great deal of research on lexical
access or word recognition, the
process by which we obtain
information about the meaning and
syntactic properties of a word from
our mental lexicon.

20. Several experimental techniques have
been used in studies of lexical access:
Lexical decision measures response time or
reaction time wherein the assumption is that
the longer it takes to respond to a particular
task, the more processing involved.
RT measurements show that lexical access
depends to some extent on word frequency;
more commonly used words (both spoken and
written) such as car are responded to more
quickly than words that we rarely encounter
such as fig.

21. Semantic priming effect arises when
semantically related words are located in
the same part of the mental lexicon, so
when we hear a priming word and look it
up in the lexicon, semantically related,
nearby words are “awakened” and more
readily accessible for a few moments.
 (say the that the word nurse primes the
word doctor)

22. One of the most interesting facts about lexical
access is that listeners retrieve all meanings of a
word even when the sentence containing the word
is biased toward one of the meanings.
The gypsy read the young man’s palm
for only a dollar.

23. Palm primes the word hand, so in lexical
decision about hand, a shorter RT occurs
than in a comparable sentence not
containing the word palm. However, a
shorter RT also occurs for the word tree.
The other meaning of palm (as in palm
tree) is apparently activated even though
that meaning is not a part of the meaning of
the priming sentence.

24. Naming task, asks the subject to read aloud a
printed word. The experiment suggests that people
can do two different things in the naming task. They
can look for the string in their mental lexicon, and if
they find it, they can pronounce the stored
phonological representation for it. They can also
“sound it out”, using their knowledge of how certain
letters or letter sequences are most commonly
pronounced.
For example: subjects read irregularly spelled
words like dough and steak just slightly more slowly
than regularly spelled words like doe and stake, but
still faster than invented strings like cluff.