A Year in Language, Day 221: Concept: Wave Model Most everyone is familiar with the tree model of historical linguistics; most dictionaries have one in the back, and a fancy dictionary will display it like an actual tree. The tree model is simple: you have an ancestral language node, that node extends downwards (or upwards) to the next language to descend from it, and splits if there is more than one language. Tree models are very tidy and good for quick reference genealogy. What they lack is the ability to deal with any form of complexity or detail beyond the most basic parent-child relationship. Where do Creoles language belong on the chart? How is one to know of the profound impact of Dravidian language on Indo-Aryan languages, and vice versa? Wave models are one way linguists have sought to more accurately display this kind of information. When looking at a wave model you might think you're looking at a topology map; a geographic region covered in outlined shapes, some nestled within one another, some intersecting like a ven diagram. On a topology map these would denote elevation, in a wave model they represent individual features of language. How specific these features are depends on the needs of the linguists; another feature of the wave model is its ability to "zoom" in and out. The waves could each represent whole dialect clusters or even the boundaries of an entire language community, or they could each represent the presence or absence of certain vocabulary items, or minute phonetic features. Wave models are very good at mapping dialect continuum like the kind found in central Europe. Wave models are likely more accurate representations of language both synchronically (i.e. at one given point in time, like the present) and diachronically (over time, i.e. historically). Languages are just bundles of features, and greater language change and the distinction between dialects are just collections of related changes in those individual features. So why aren't wave models more common? Well, they're frankly much more difficult to read at a glance. Its important for the historian, anthropologist, or linguist to understand how, say, the evolution of the Polynesian languages is more complex than simply one parent language creating two distinct daughters, but its a bit much for someone who was just interested in trivia, or simply not initiated to that level of academia.
