There are languages, however, in which such differences are of the most fundamental grammatical importance.  They are particularly common in the Soudan.  In Ewe, for instance, there are formed from subo “to serve” two reduplicated forms, an infinitive subosubo “to serve,” with a low tone on the first two syllables and a high one on the last two, and an adjectival subosubo “serving,” in which all the syllables have a high tone.  Even more striking are cases furnished by Shilluk, one of the languages of the headwaters of the Nile.  The plural of the noun often differs in tone from the singular, e.g., yit (high) “ear” but yit (low) “ears.”  In the pronoun three forms may be distinguished by tone alone; e “he” has a high tone and is subjective, _-e_ “him” (e.g., a chwol-e “he called him”) has a low tone and is objective, _-e_ “his” (e.g., wod-e “his house”) has a middle tone and is possessive.  From the verbal element gwed- “to write” are formed gwed-o “(he) writes” with a low tone, the passive gwet “(it was) written” with a falling tone, the imperative gwet “write!” with a rising tone, and the verbal noun gwet “writing” with a middle tone.  In aboriginal America also pitch accent is known to occur as a grammatical process.  A good example of such a pitch language is Tlingit, spoken by the Indians of the southern coast of Alaska.  In this language many verbs vary the tone of the radical element according to tense; hun “to sell,” sin “to hide,” tin “to see,” and numerous other radical elements, if low-toned, refer to past time, if high-toned, to the future.  Another type of function is illustrated by the Takelma forms hel “song,” with falling pitch, but hel “sing!” with a rising inflection; parallel to these forms are sel (falling) “black paint,” sel (rising) “paint it!” All in all it is clear that pitch accent, like stress and vocalic or consonantal modifications, is far less infrequently employed as a grammatical process than our own habits of speech would prepare us to believe probable.

V

FORM IN LANGUAGE:  GRAMMATICAL CONCEPTS

We have seen that the single word expresses either a simple concept or a combination of concepts so interrelated as to form a psychological unity.  We have, furthermore, briefly reviewed from a strictly formal standpoint the main processes that are used by all known languages to affect the fundamental concepts—­those embodied in unanalyzable words or in the radical elements of words—­by the modifying or formative influence of subsidiary concepts.  In this chapter we shall look a little more closely into the nature of the world of concepts, in so far as that world is reflected and systematized in linguistic structure.