Notes on computational linguistics.pdf - UCLA Department of ...

Stabler - Lx 185/209 2003
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1.4 Some distinctions of human languages
Even if we regard human languages as logics, it is easy to see that they differ in some fundamental respects
from logics like the propositional calculus. Let’s quickly review some of the most basic properties of human
languages, many of which we will discuss later:
1. To a first approximation, the physical structure of an utterance can be regarded as a sequence of perceivable
gestures in time. We will call the basic elements of these sequences perceptual atoms.
2. Utterances have syntactic and semantic structure whose atoms are often not perceptual atoms, but perceptual
complexes.
3. Properties of atoms are remembered; properties of complexes may be calculated or remembered.
At any time, the number of remembered atomic properties (perceptual, syntactic, semantic) is finite.
4. A sequence of perceptual atoms that is a semantic or syntactic atom in one context may not be one in
another context.
For example, in its idiomatic use, keep tabs on is semantically atomic, but it has literal uses as well in which it is
semantically complex.
5. In every human language, the sets of perceptual, syntactic, and semantic atoms may overlap, but they are
not identical.
6. Every human language is open-ended: ordinary language use involves learning new expressions all the time.
7. In every human language, the interpretation of many utterances is context dependent.
For example, it is here is only true or false relative to an interpretation of the relevant context of utterance.
8. Every language has expressions denoting properties, relations, relations among properties and relations,
quantifiers and Boolean operations. Some of the relations involve “events” and their participants.
“Agents” of an event tend to be mentioned first
9. In every human language, utterances can be informative.
Humans can understand (and learn from) sentences about individuals and properties that we knew nothing
of before.
So, for one thing, declarative sentences do not mean simply true or false.
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