Language Change Occurs in Rapid Bursts

I seem to be reading a lot of news from New Zealand and Australia lately ...

This article http://www.sciencealert.com.au/news/20080502-16846-5.html concerns research on change between two languages that have diverged from one. It mentions that much of the vocabulary change occurs rapidly at 'language-splitting events.' It has long been assumed that change happens slowly over time.

The article doesn't go into any detail into what constitutes a 'language-splitting event.' But, since much of the research was done in the Pacific, my first impression was to imagine a group of people packing up and moving to another island, exposing themselves and their language to a new environment and new influences. Another possible 'language-splitting event' the article hints at is when social groups deliberately alter their language in order to distinguish themselves from each other.

This revelation in language evolution seems to parallel findings in Darwinian evolution. It was long thought that evolution occurs slowly over long periods of time, but more recent evidence suggests that significant 'events' force rapid evolutionary changes, followed by long, relatively static periods.