【单选题】

The languages of the world can be divided into a number of families of related languages, possibly grouped into larger stocks, plus a residue of isolates, languages that appear not to be genetically related to any other known languages, languages that form one-member families on their own. The number of families or stocks, languages, and isolates is hotly disputeD、The disagreements centre around differences of opinion as to what constitutes a family or stock, as well as the acceptable criteria and methods for establishing them.

Linguists are sometimes divided into lumpers and splitters according to whether they lump many languages together into large stocks, or divide them into numerous smaller family groups. Merritt Ruhlen is an extreme lumper: in his classification of the world’s languages he identifies just nineteen language families or stocks, and five isolates. More towards the splitting end isEthnologue, which identifies some ninety-four top-level families, as well as thirty-six isolates, and forty-three unclassified languages.About two hundred other exceptional languages are identified as well, including deaf sign languages.Even so, in terms of what has actually been established by application of the comparative method, theEthnologue system is wildly lumping!
Some families, for instanceAustronesian and Indo-European, are well established, and few serious doubts exist as to their genetic unity. Others are quite contentious.Both Ruhlen andEthnologue identify anAustralian family, although there is as yet no firm evidence that the languages of the continent are all genetically relateD、At least as contentious is Joseph Greenberg’s putativeAmerind stock of NativeAmerican languages.
The Indo-European languages have been recognized as forming a family since at .least the late seventeenth century, whenAndreas Jager observed in 1686 that Persian and many of the languages ofEurope are descendants of a single language. Since Jager’s time, many more languages have been shown to belong to the family. Indeed, Indo-European languages are spoken throughout most ofEurope, across Iran, throughCentralAsia, and into IndiA、With the colonial expansions of the fifteenth to nineteenth centuries, they spread into theAmericas,Australia, New Zealand,Africa, andAsia, in the process diversifying into numerous dialects. They have become major languages in many of the former colonies, and are spoken by a staggering two and a half billion speakers.
The family consists of just over 400 languages (430 according to the latest edition ofEthnologue), which can be grouped together into a number of subfamilies or branches.
More historical-comparative work has been done on Indo-European than any other language family, and many lexemes have been reconstructed for proto-Indo-European, as well as some of its grammar. Proto-Indo-European was an inflecting language, like ancient IndoEuropean languages such as Latin, Hittite andAncient Greek, with a complex verbal system with different inflections for different persons and numbers of the subject, tense, aspect, mood, as well as case-marking for nouns.
Proto-Indo-European is widely believed to have been spoken in the southeast ofEurope, perhaps in the region of Turkey, some six to eight thousand years ago. Opinions differ, however, and some argue for a more northerly location in the steppes of RussiA、From the homelands the language spread east and west, in the process fragmenting into numerous mutually unintelligible languages.
It is now widely believed that the early period of Indo-European expansion that took the languages as far as India in the east and Ireland in the west, was not via military style invasions like the Roman conquests of 2,000-odd years ago. One influential idea is that the expansion of the languages accompanied the spread of agriculture from a centre in the near east, beginning some six to eight thousand years ago.Ac