HUMAN SPEECH 47 



For some, in fact for most languages, however, literary monuments 

 are either not forthcoming at all or else are restricted to a single 

 period of short duration. At first sight it would seem that the sci- 

 entific study of such languages would have to be limited to purely 

 descriptive rather than historical data. To a considerable extent this 

 is necessarily true, yet an intensive study will always yield at least 

 some, oftentimes a great deal of, information of a historical char- 

 acter. This historical reconstruction on the basis of purely descrip- 

 tive data may proceed in two ways. It is obvious that the various 

 phonetic and grammatical features of a language at any given time 

 are of unequal antiquity, for they are the resultants of changes that 

 have taken place at very different periods; hence it is reasonable 

 to suppose that internal evidence would, at least within modest 

 limits, enable one to reconstruct the relative chronology of the lan- 

 guage. Naturally one must proceed very cautiously in reconstruct- 

 ing by means of internal evidence, but it is oftentimes surprising how 

 much the careful and methodically schooled student can accomplish in 

 this way. Generally speaking, linguistic features that are irregular in 

 character may be considered as relatively archaic, for they are in the 

 nature of survivals of features at one time more widely spread. Not 

 infrequently an inference based on internal evidence can be corrobo- 

 rated by direct historical testimony. One example will suffice here. 

 "We have in English a mere sprinkling of noun plurals in -en, such as 

 brethren and oxen. One may surmise that nouns such as these are but 

 the last survivals of a type formerly existing in greater abundance, and 

 indeed a study of Old English or Anglo-Saxon demonstrates that noun 

 plurals in -en were originally found in great number but were later 

 almost entirely replaced by plurals in -s. There is, however, a far 

 more powerful method of reconstructing linguistic history from de- 

 scriptive data than internal evidence. This is the comparison of genet- 

 ically related languages. 



In making a survey of the spoken languages of the world, we soon 

 find that though they differ from each other, they do so in quite vary- 

 ing degrees. In some cases the differences are not great enough to 

 prevent the speakers of the two languages from understanding each 

 other with a fair degree of ease, under which circumstances we are apt 

 to speak of the two forms of speech as dialects of a single language ; in 

 other cases the two languages are not mutually intelligible, but, as in 

 the case of English and German, present so many similarities of detail 

 that a belief in their common origin seems warranted and indeed nec- 

 essary; in still other cases the two languages are at first glance not at 

 all similar, but reveal on a closer study so many fundamental traits 

 in common that there seems just ground for suspecting a common 

 origin. If other languages can be found winch serve to lessen the 



