Ambiguity 'makes language more efficient'

Ambiguity actually makes language more efficient, by allowing for the reuse of short, efficient sounds that listeners can easily disambiguate with the help of context, researchers have claimed.

Many prominent linguists, including MIT's Noam Chomsky, have argued that language is, in fact, poorly designed for communication. Such a use, they say, is merely a byproduct of a system that probably evolved for other reasons, perhaps for structuring our own private thoughts.

As evidence, these linguists point to the existence of ambiguity: In a system optimized for conveying information between a speaker and a listener, they argue, each word would have just one meaning, eliminating any chance of confusion or misunderstanding.

Now, a group of MIT cognitive scientists has turned this idea on its head. In a new theory, they claim that ambiguity makes language more efficient.

"Various people have said that ambiguity is a problem for communication," Ted Gibson, senior author of the study, said.

"But once we understand that context disambiguates, then ambiguity is not a problem ufffd it's something you can take advantage of, because you can reuse easy words in different contexts over and over again," he said.

For an ironic example of ambiguity, the word "mean" can be used to indicate or signify, but it can also refer to an intention or purpose, something offensive or nasty, or the mathematical average of a set of numbers.

However, virtually no speaker of English gets confused when he or she hears the word "mean" because the different senses of the word occur in such different contexts as to allow listeners to infer its meaning nearly automatically.

Given the disambiguating power of context, the researchers hypothesized that languages might harness ambiguity to reuse words ufffd most likely, the easiest words for language processing systems. Building on observation and previous studies, they posited that words with fewer syllables, high frequency and the simplest pronunciations should have the most meanings.

To test this prediction, Piantadosi, Tily and Gibson carried out corpus studies of English, Dutch and German.

In linguistics, a corpus is a large body of samples of language as it is used naturally, which can be used to search for word frequencies or patterns.

By comparing certain properties of words to their numbers of meanings, the researchers confirmed their suspicion that shorter, more frequent words, as well as those that conform to the language's typical sound patterns, are most likely to be ambiguous ufffd trends that were statistically significant in all three languages.

To understand why ambiguity makes a language more efficient rather than less so, think about the competing desires of the speaker and the listener. The speaker is interested in conveying as much as possible with the fewest possible words, while the listener is aiming to get a complete and specific understanding of what the speaker is trying to say.

But as the researchers write, it is "cognitively cheaper" to have the listener infer certain things from the context than to have the speaker spend time on longer and more complicated utterances.

Piantadosi said that the result is a system that skews toward ambiguity, reusing the "easiest" words. Once context is considered, it's clear that "ambiguity is actually something you would want in the communication system."

The study has been published in the journal Cognition.