2.  What is a word?
 Native speakers of a language seem to know intuitively
what a word is in their language.
 OAD definition: language need not be written, but they still
have words, and words do not have blank space between
them in spoken form of language.
 Morphologists, however, have the luxury of being more
precise: we can define a word as a sequence of one or
more morphemes that can stand alone in a language.
 Is xyz a word?

3. In general conversation, in reading an article or newspaper we will look to the dic
for an answer.
Which dictionary?
Depends on what you want? My be you will search taboo words or very new words
that is not find in the largest on line oxford dic.
Nonce, mistakes, and mountweazels: sometime we find items in dic that we might
hesitate to call words-even if they do occur in the dic.
Nonce is meaning that they have found just once, often in the writing of someone
important, but that nevertheless don’t not seem to occur anywhere else.
For example:agreemony,which they define as agreeableness , and illustrate with a
single quotation from 17 centaury writer Aphra Behan.
As you know extensive dic like OED sometimes also contain words that they
identify as mistakes.
For example: ambassady, which occurs in single quotation from 1693 and is
according to OED, perhaps a mistake, where it means ambassade the mission
of function of an ambassador.
A mountweazel is a phony word that is inserted in to a dic so that is markers can
identify lexicographic piracy. Lexicographer sometimes makes up an entry and
include it so that they can tell if another one is using their dic as a source
without attribution(which is plagiarism, of course).

4. Dictionary do not need to include every word. every language
has ways of forming new words so putting all of forming of
new word would be waste of space.
For example: speakers of English know that any verb at all
can have a present progressive form made with the suffix-
ing . As soon as we make new verb, say zax, we know that
the present progressive verb form zaxing .so although a
dic have to include the verb zax bout never include all of
forms. they sometimes include words used only once
whose meaning are completely unknown.dic do not fix or
codify the words of language, but rather reflect the words
that native speakers use. those words are encoded in what
we will call the mental lexicon. Totally of word knowledge
that native speakers carry around in their heads.

5. Mental lexicon is the knowledge includes information about
pronunciation, category, meaning, syntactic properties,
level of formality, that speaker of specific language have in
their mind.
Each persons mental lexicon is contain things that are
different from other peoples mental lexicons. For example
one person may know lots of words for type of birds or
flowers, another might know all the specialized voc of
sailing ,and so on.
How many words?
Psycholinguistics estimate that average English speaking 60
years old knows 10000 words, and high school graduated
60000 words. Pauk Bloom describe how this estimate can
be made: if you use dic with 500000 words, and test
people on a 500-word sample, you would determine the
number of English words they know by taking the number
that they got correct from this sample and multiply by
1000.

6. The acquisition of lexical knowledge
Someone thinks that learning new word would be easy, for
instance someone points at something and says flower and
you learn that that something is called a flower. This may be
the way that we learn some words in our mental lexicons. But
sometimes it is not clear from the context what exactly is
being pointed out. Psycholinguistics sometimes call this the
Gavagai problem.
There are several things that we do know about how word
learning occurs:
Susan Carey believed that both children and adults are able to
do what she has called fast mapping ,it is the ability to pick
up new words on the basis of a few random to see them.
During an unrelated activity ,they were able to absorb the
word and recall it even six weeks later, for example Dolphin.
while the ability to learn linguistic rules such as syntax or
phonology is thought to decline after puberty.
Another strategies are: lexical contrast principle ,learner will
always assume that a new word refers to sth that dose not
already have name.
Whole object principle, whole unnamed object to be flower.
They will not assume that flower refers to part of object, to its
color or shape, or to a super ordinate of objects to which it
might belong.

7. Mutual exclusivity principle, there are only familiar object for which
subjects already have names, will assume that if an object already
has a word for it, the word flower cannot be synonymous with those
words.
The organization of the mental lexicon: strong versus rules
Mental lexicon can not be organized alphabetically like dic. it is complex
web composed of stored items (morpheme,words,idiomatic
phrases)that may be related to each other by the sound or meaning.
Steven pinker call the words and rules theory of mental lexicon. We
know that speaker of specific language has an unconscious
knowledge of the past tense rules because they can automatically
create the past tense of verb.
Evidence from aphasia
This class of language disorder ranges from having difficulty
remembering words to losing the ability to speak, read, or writing.
Some aphasics display agrammatism this means that they have
difficulty in producing or processing function words in sentence, but
can still produce and understand content words. For example those
with suffixes that we use frequently in making up new words-less as
in shoeless or –ly as in darkly whereas they have less trouble with
irregular forms like sang and flew.

8. Other aphasics display jargon aphasia: these aphasics
produce fluent sentence using function words, but have
trouble producing and understanding content words. They
will use regular inflections appropriately on their nonsense
words, but they have difficulty processing and producing
irregular forms. For agrammatism aphasics, the irregular
forms have been lost because the part of the brain that
apparently allows access to stored forms has been
damaged, but the regular rule is still intact. For example
they can make past tense of played but cannot make past
tense of go.
Evidence form imaging studies: imaging studies of
normal subjects, such as those done with PET (position
emission tomography)scans measure the level of blood
flow to different parts of the brain, which in turn shows us
areas of activation in those parts. there are parts of the
brain that are activated when subjects are asked to read
regularly inflected past tenses that are distinct from those
activated in reading or producing irregular past tense.

9. Evidence from genetic disorders: two different genetic
disorders
Specific language impairment(SLI) and Williams Syndrome
SLI are generally of normal intelligence and have no hearing
important, just they are slow to produce and understanding
language, and their speech is characterized by omission of
various inflectional morphemes. They difficult to create the
past tenses of novel verb, and often fail to inflect unfamiliar
regular verbs correctly. They have less difficulty with irregular
verbs, thought. In spontaneous speech, they may leave the
regular past tense off verbs.
Williams syndrome have genetic disorder linked to various heart
problems, high levels of calcium in their blood, and a
characteristic appearance. Their language and social skills are
in normal rang, but have got mental lexicon problem. they
speak fluently and produce sentence with correct regular past
tense, but have more trouble with irregular ones, indeed they
seem to use regular past tense marking even where control
subjects or individuals with SLI would not for example,
overgeneralizing the regular –ed ending on irregular
verbs(falled)

10. Reprise: is it really a word?
Most morphologists would say that if a word can be formed
by the rules of word formation in a particular language, it
will be word the same as xyz .
As you know, it is the rule of word formation that we know
that most distinguish our mental lexicon from the dic.