Ambiguity

Vagueness Underspecificity

LIN 141: Semantics

Masoud Jasbi

Ambiguity

What is ambiguity?

Mention some examples of ambiguity you know.

Why do you think language has ambiguity?

What are the sources of ambiguity?

Ambiguity

“Ambiguity” is ambiguous!

We can say a word, phrase, or utterance is ambiguous if:

1. It has more than one interpretation.
2. We are uncertain what the exact interpretation is.

Technically “ambiguity” refers to the first.

We’ll have other words for the second:

underspecificity, vagueness, and context-sensitivity.

Factors affecting ambiguity

Ambiguity

(nontechnical)

Ambiguity

(technical)

Underspecificity

Vagueness

Context-Sensitivity

...

Methodology

Ambiguity is not one thing!

Studying ambiguity is like determining a recipe by only tasting a soup.

Figure out the ingredients, the amounts, the way they were combined

chopped, mixed, cooked, heated, etc…

Some ingredients are present in some soups but not others.

Some ingredients are present in almost every soup.

In both cases, the amount (degree) matters!

The same is true about factors that contribute to ambiguity (and interpretation).

Factors affecting ambiguity in language

Let’s talk about each of these briefly

1. Context-sensitivity
2. Underspecificity
3. Vagueness
4. Ambiguity (technical)

Context-sensitivity

The interpretation of an expression is context-sensitive/dependent if:

it is determined by the discourse context.

radically changes from context to context.

The interpretation of an expression is context-independent if:

it is not determined by the discourse context.

it is constant across contexts.

Name some words with context-independent meanings.

Every expression is to some degree context-sensitive.

Context-sensitivity (strict sense)

The meaning or interpretation of an expression is context-sensitive in a strict sense if its truth conditions rely on the discourse context.

1. Every Simpson is happy.
2. That Simpson is happy.

Pronouns and demonstratives are the classic case of context-sensitive expressions in the strict sense.

Underspecificity

An expression can leave further details of its meaning unspecified, without giving rise to multiple meanings or interpretations.

Example 1 (English):

I said hello to my uncle.

Example 2 (Persian):

be amu goft-am salam

to uncle.from.fathers.side say-1.SG hello

“I said hello to my uncle (from father’s side)”

More Examples of Underspecificity

Gender: Who said hello to who?

Example 3 (English): Bob and Cleo met ...

She said hello to him.

Example 4: Bob and cleo met ...

un be-sh salam kard-

that to-3.SG hello do

“S/he/it said hello to him/her/it”

More Examples of Underspecificity

Affectedness: was the canvas slashed?

(1) Barbara slashed the canvas.

(2) Barbara slashed at the canvas.

Motion: which object was moving?

(3) The truck and the car collided.

(4) The truck collided with the car.

Ever since it started snowing, all my roommate has done is stare through the window.

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If it gets any worse, I’ll have to let him in.

“stare through the window”

Construal 1

Construal 2

Scopal Specificity

∀y[∃x[annoy(x,y)]]

Everyone is annoyed by someone (different).

∃x[∀y[annoy(x,y)]]

Everyone is annoyed by someone (specific).

∀y[∃x[annoy(x,y)]]

Everyone is annoyed by someone (different).

∃x[∀y[annoy(x,y)]]

Everyone is annoyed by someone (specific).

∃x[∀y[...]

⇒

∀y[∃x[...]

∀y[∃x[...]]

⇏

∃x[∀y[...]]

Vagueness

A term is vague to the extent that it has borderline cases.

“A proposition is vague when there are possible states of things concerning which it is intrinsically uncertain whether, had they been contemplated by the speaker, he would have regarded them as excluded or allowed by the proposition. By intrinsically uncertain we mean not uncertain in consequence of any ignorance of the interpreter, but because the speaker’s habits of language were indeterminate. (Peirce 1902, 748)”

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Charles Sanders Peirce

(1839 – 1914)

Vagueness in Philosophy

If you cut one head off of a two headed man, have you decapitated him?

Where does the tail of a snake begin?

What is the maximum height of a short man?

Sorites Paradox:

• A $7 cup of coffee is expensive (for a cup of coffee).
• Any cup of coffee that costs 1 cent less than an expensive cup of coffee is expensive (for a cup of coffee).
• Therefore, any free cup of coffee is expensive.

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Vagueness and Context

1. Abe is tall.
2. Abe is a basketball player.
3. Therefore Abe is a tall basketball player.

Does (c) follow from (a) and (b)?

Not only tall is vague, it also context-sensitive!

It relies on a standard of comparison in context.

Ambiguity (Technical)

An expression in language is ambiguous if it gives rise to more than one distinct interpretation.

We reserve the term for cases that require different entries in our lexicon.

Types of Ambiguity:

Phonological

Lexical

Syntactic

Pragmatic, ...

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Phonological Ambiguity

When the same sequence of sounds can correspond to different words.

Taylor Swift’s Blank Space lyrics:

1. All the lonely Starbucks lovers.
2. Got along with Starbucks lovers.
3. Got a long list of ex-lovers.

Lexical Ambiguity

Classic case: a word that has more than one distinct meaning.

1. The bat flew away ...
1. as the player hit the ball.
2. and flapped its wings very hard.
2. The bank is close.
• We can picnic there.
• We can get cash.
3. That character is bright.
• She can solve all sorts of puzzles.
• Can you make it darker?

Idioms

A similar pattern is present with phrases and sentences that can act as idioms.

• Break a leg! ...
• said her dad.
• said the mafia boss.
• Bob and Barbara are not on the same page.
• Barbara is going to finish the book earlier.
• They may get into a fight.
• Abe put all his eggs in one basket.
• And headed towards the checkout counter.
• And therefore lost all he had.

Syntactic Ambiguity

An ambiguity is classified as syntactic when the difference in meaning can be traced back to different syntactic structures generated by our grammar.

Scope Ambiguity

Scope ambiguity is the type of ambiguity that can be explained by the (syntactic) order of the operators (like quantifiers) in your semantic theory.

1. A woman gives birth in the UK every 48 seconds.
1. She must be exhausted.
2. They all receive free NHS care.
2. Bob didn’t want a car or a motorbike.
• Can’t remember which.
• He wanted to only use public transport.

Scope ambiguity can be regarded as a type of syntactic ambiguity.

Puzzle

What type of ambiguity is this joke using?

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Patient: Doctor! I've broken my leg in three places!

Doctor: Well, don't go to those places then.

Capturing Ambiguity

How can our models capture different types of ambiguity?

• Lexical Ambiguity:
• assign distinct meanings to individual words/phrases
• show that some words have more than one meaning.
• Syntactic Ambiguity:
• assign distinct syntactic structures to the same linguistic expression
• show that each interpretation corresponds to each distinct syntactic composition.
• Scopal ambiguity:
• assign distinct arrangement of scope taking operators
• show that each interpretation is captured by one arrangement.