Answer three of the following. Try not to spend more than two
hours on the exam altogether.
Submit your answers to me
by email by 12:01 am, Thursday,
Oct. 22. Please include "645" somewhere in the subject of your
message.
If you have questions about the exam, send me a message, again
including "645" in the subject.
The regular past tense morpheme of English, spelled -ed,
has three pronunciations depending on the consonant or vowel that
precedes it.
If it is preceded by /t/ or /d/, it is pronounced /@d/,
where /@/ is an ascii representation of a central vowel (schwa).
Otherwise,
if it is preceded by a voiceless consonant (/p/, /f/, /s/, /ch/, /sh/,
or /k/), it is pronounced /t/.
Otherwise it is pronounced /d/.
We can view the past tense morpheme as having the underlying (lexical)
form /d/ and being subject to two rules,
(1) a rule which inserts the vowel /@/ between a preceding /t/ or /d/
and the past-tense /d/
and (2) a rule which changes /d/ to /t/ following a voiceless
consonant. Rule (1) must precede rule (2).
Thus for ripped, we have
rIp+d -> rIpt (by rule (2))
and for fitted, we have
fIt+d -> fIt@d (by rule (1))
Explain how these rules would be implemented in the two-level
(KIMMO) framework.
Show how this approach would produce the surface form /rIpt/
(ripped) starting with the lexical form /rIp+d/.
In English, indefinite articles (a(n), some)
must agree with the nouns they modify.
Singular count nouns such as cat and idea take
a(n) while mass and plural nouns such as cheese,
air, and cats take some.
Explain why a simple context-free grammar without features
would be an inefficient way to deal with this phenomenon.
Explain how a feature-based grammar would handle it.
You needn't include all of the HPSG structure (SYNSEM, DTRS, etc.).
Show how your grammar would fail to parse the
ungrammatical noun phrase cat.
Explain how a chart parser might deal with the following sentence
containing an unfamiliar word:
The girl kicked the zibby.
Assume your parser can return a partial parse, which could be used by
a learning component to figure out the parts that weren't understood.
You can use a simple featureless (non-HPSG) context-free grammar if
you like.
Both morphology and syntax are concerned with structure, the structure
of words in the case of morphology, the structure of sentences in the
case of syntax.
As we have seen, quite different mechanisms are called for in the two
cases.
Contrast the task of processing morphology with that of processing
syntax, and discuss why different mechanisms are required.
Give examples.