Cross-linguistic comparisons serve as empirical tests generating evidence for and against lexical ambiguity in words like “good”, “know”, “the”, “can”, and “may”. Critics question such comparisons' validity. This article examines how cross-linguistic comparisons are treated as tests and shows that they have two predominant forms: one modeled on modus tollens, and another on Bayes' theorem, where the former is an enthymematic version of the latter. This analysis reveals the strengths and weaknesses of cross-linguistic comparisons, and thereby guides interpretation of their (...) results. It concludes that cross-linguistic comparisons generally yield stronger evidence against lexical ambiguity than for it. (shrink)

Efficiency principles are increasingly called upon to study features of human language and communication. Zipf's law of abbreviation is widely seen as a classic instance of a linguistic pattern brought about by language users’ search for efficient communication. The “law”—a recurrent correlation between the frequency of words and their brevity—is a near-universal principle of communication, having been found in all of the hundreds of human languages where it has been tested, and a few nonhuman communication systems as well. The standard (...) explanation for the law of abbreviation derives from pressures for efficiency: speakers minimize their cumulative effort by using shorter words for frequent occurrences. This explanation, we argue here, fails to explain why long words exist at all. It also fails to explain why the law of abbreviation, despite being robust, is systematically weakened by many short and rare words. We propose an alternative account of the law of abbreviation, based on a simple cultural evolutionary model. Our model does not require any pressure for efficiency. Instead, it derives the law of abbreviation from a general pressure for brevity applying to all words regardless of their frequency. This model makes two accurate predictions that the standard model misses: the correlation between frequency and brevity is consistently weak, and it is characterized by heteroskedasticity, with many short and rare words. We argue on this basis that efficiency considerations are neither necessary nor sufficient to explain the law. (shrink)