Assignment 1 solution, Ling 645/CMSC 723, Fall 1997


Assignment 1a:  ELIZA [10 points]

     "Play with the program for a while: can you get it to
     have a reasonably natural sounding dialogue for a sentence
     or two?  If so, what makes it natural?  If not, what are 
     the obstacles?"

  N.B. Deducted 5 points for no transcript.

Assignment 1b: 

  Allen, Chapter 1, Exercise 2 [40 points]

    a.  Time flies like an arrow

      This example comes from an old line by the comedian Groucho Marx:
      "Time flies like an arrow.  Fruit flies like a banana."
      Groucho's humor is often linguistically interesting!  Take a look
      at .

      Some paraphrases of possible meanings.

	1.  Time goes by as quickly as an arrow.

	2.  There exists a particular arrow x such that every
	    "time fly" (a kind of insect) likes x.  
	    (Many flies, one arrow)

	3.  For every every "time fly" (a kind of insect) y,
	    there is an arrow x such that y likes x.  
	    (Many flies, one arrow per fly)

	4.  Someone or something named "Time" flies in a way 
	    similar to an arrow.  E.g. "Mr. Time flies an airplane
	    fast and straight."

      The difference between 1 and (2,3) arises because of syntactic 
      (or lexical) ambiguity:  "like" can be either a comparative
      preposition (meaning 1) or a verb (meanings 2 and 3).   A
      structural ambiguity (whether "time flies" is a noun phrase
      or not) goes along with that.  Meanings 1 vs. 4 illustrate a word
      sense ambiguity between "fly" as verb in its sense of going
      by quickly and in its literal sense of something flying through
      the air.

      The difference between 2 and 3 is a semantic ambiguity, often referred
      to as a "scope" ambiguity because it involves the scope of
      quantifiers in the first-order logic representation of the
      sentence's meaning.  A clearer example:  "Every company hires
      a programmer."  This could mean there's a single programmer, call
      him Edgar, that is hired by every company.  It could also mean that
      for every company, there's some programmer that it hires; e.g. IBM
      hires Edgar, Microsoft hires Walter, etc.

    b.  He drew one card.

      1.  He took one playing card out of a deck of cards.

      2.  He drew a picture of one card.

      This is a semantic ambiguity, specifically a word sense ambiguity.
      The verb "draw" can refer to two different kinds of actions.

    c.  Mr. Spock was charged with illegal alien recruitment.

      1.  Mr. Spock was charged with illegally recruiting aliens;
	  that is, recruiting ALIENS is against the law and Mr. Spock
	  did it anyway.

      2.  Mr. Spock was charged with recruiting illegal aliens;
	  that is, recruiting ILLEGAL ALIENS is against the law,
	  and Mr. Spock did it anyway.

      This is a syntactic ambiguity:  the noun phrase "illegal
      alien recruitment" can be analyzed either as 
      "illegal (alien recruitment)" (meaning 1) or as 
      "(illegal alien) recruitment" (meaning 2).  Generally,
      compounds of this kind are a really hard problem in syntactic
      analysis.  Consider: how many different analyses are there for 
      "the Washington university telephone operator"?

    d.  He crushed the key to my heart.

      1.  There is something I'm calling "the key to my heart"
	  and he crushed it.  ("The key to my heart" is a common
	  metaphor: if someone holds the key to your heart, it means,
	  roughly, that you love them.)

      2.  There was a literal key, and he crushed it against my heart.
	  (Compare:  "He crushed the flower to his cheek")

      This is another syntactic ambiguity, with semantic overtones.
      On reading 1, the verb "crush" is being used in a simple transitive
      structure, He crushed X, and the prepositional phrase "to my heart"
      is embedded in X.  On reading 2, the prepositional phrase is
      attached to the verb, He crushed X to Y, on analogy with
      "He raised the fork to his lips".  Although this can be viewed
      strictly as a matter of syntax, I think you could also see this as 
      involving semantics to some extent, specifically a semantic
      difference between two uses of crush, one of which involves
      affecting an object (by crushing it) and the other of which
      involves acting on two objects (the thing being crushed 
      and the thing/location it's being crushed to) without affecting
      the first object by changing its shape, etc.

    You'll note that I didn't find ANYTHING in the above problems that
    looked like a "pragmatic ambiguity"; I'm not 100% sure what Allen
    means by this.  My best take on what a "pragmatic ambiguity" would be
    like might be the sentence 

      He ran.

    which can mean "He ran away" or "He ran his usual 2 miles for
    exercise"; It is underspecified semantically, and context can

    I didn't see ambiguity of that kind, but still, here are some of the
    pragmatic/contextual issues raised by the examples.

    Problem (a) is pragmatically very odd on any but the first reading,
    unless "time flies" have already been introduced into the context as
    something that can be referred to.  It is in fact possible to refer to
    things that have not been introduced before -- technically this is
    often called "accommodation" because the hearer accommodates the
    speaker by introducing objects that are required for the sentence to
    be understood.  However, it is pragmatically inappropriate for a
    speaker to expect the hearer to accommodate a new term (e.g. "time
    flies") when there's another more obvious reading (namely meaning 1).

    In problem (b), notice that it would be fine, pragmatically, to begin
    a story wih the sentence if what you meant was meaning 1.  This would
    be accommodation again: you're using "draw a card" as a phrase, and
    even though there isn't a particular deck of cards in the context,
    it's ok because when "draw" and "card" are used together, that evokes
    in the hearer's mind a context where a card game is being played.
    (This is a case where both words are semantically ambiguous, but the
    pragmatics helps resolve the ambiguity.)  On the other hand, for
    precisely this reason, it would be pragmatically infelicitous to 
    start a story with this sentence if meaning 2 was intended.

    In problem (c), I think reading 1 is pragmatically more felicitous,
    since Mr. Spock is conventially associated with a context (the
    futuristic world of Star Trek) in which aliens (but not illegal
    aliens) are a part of daily life.

    In problem (d), I think both readings are essentially ok
    pragmatically, although "the key to my heart" is enough of a familiar
    phrase that I think reading 2 might be a little bit less good
    pragmatically than reading 1.

  Allen, Chapter 2, Exercise 2  [20 points]

    I've given heads of constituents in uppercase

    The man played his fiddle in the street

      NP:  the MAN
      VP:  PLAYED his fiddle in the street 
	NP:  his FIDDLE
	PP:  IN the street
	  NP:  the STREET

    The people dissatisfied with the verdict left the courtroom

      NP: The PEOPLE dissatisfied with the verdict
	  PP: WITH the verdict
	  NP: the VERDICT
      VP: LEFT the courtroom

  Allen, Chapter 2, Exercise 4  [20 points]

    These are worth 4 points each; make deductions based on
    the clarity of the answer.  I'm going to give a "must mention"
    for each one, and if not mentioned, make it a minimum 2-pt

    a. He barked the wrong tree up

      Here 'up' is a preposition, not a particle, and so it
      may not follow the object NP.  (Allen, p. 31)

    b. She turned waters into wine.

      'Water' is a mass noun, so the plural form here is not ok.
      (Allen, p. 26, although, to be fair, there is a POSSIBLE 
      reading where the plural is ok.)  

    c.  Don't take many all the cookies!

      You can only have one quantifying determiner in a noun phrase.
      (Allen, p. 27)  

    d.  I feel floor today.

      'Floor' is not an ADJP, as the complement of 'feel' must
      be; cf. I feel SAD today.  Alternatively, 'floor' is missing
      a determiner; cf. I feel THE FLOOR today (with my hands).
      (Allen, pp. 33, 35)

    e.  They all laughed the boy.

      'Laugh' cannot be transitive.  (Allen, p. 30)

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