Every linguist knows that phonetic change is frequently followed by morphological rearrangements, but he is apt to assume that morphology exercises little or no influence on the course of phonetic history. I am inclined to believe that our present tendency to isolate phonetics and grammar as mutually irrelevant linguistic provinces is unfortunate. There are likely to be fundamental relations between them and their respective histories that we do not yet fully grasp. After all, if speech sounds exist merely because they are the symbolic carriers of significant concepts and groupings of concepts, why may not a strong drift or a permanent feature in the conceptual sphere exercise a furthering or retarding influence on the phonetic drift? I believe that such influences may be demonstrated and that they deserve far more careful study than they have received.
This brings us back to our unanswered question: How is it that both English and German developed the curious alternation of unmodified vowel in the singular (foot, Fuss) and modified vowel in the plural (feet, Füsse)? Was the pre-Anglo-Saxon alternation of fot and föti an absolutely mechanical matter, without other than incidental morphological interest? It is always so represented, and, indeed, all the external facts support such a view. The change from o to ö, later e, is by no means peculiar to the plural. It is found also in the dative singular (fet), for it too goes back to an older foti. Moreover, fet of the plural applies only to the nominative and accusative; the genitive has fota, the dative fotum. Only centuries later was the alternation of o and e reinterpreted as a means of distinguishing number; o was generalized for the singular, e for the plural. Only when this reassortment of forms took place[161] was the modern symbolic value of the foot: feet alternation clearly established. Again, we must not forget that o was modified to ö (e) in all manner of other grammatical and derivative formations. Thus, a pre-Anglo-Saxon hohan (later hon) “to hang” corresponded to a höhith, hehith (later hehth) “hangs”; to dom “doom,” blod “blood,” and fod “food” corresponded the verbal derivatives dömian (later deman) “to deem,” blödian (later bledan) “to bleed,” and födian (later fedan) “to feed.” All this seems to point to the purely mechanical nature of the modification of o to ö to e. So many unrelated functions were ultimately served by the vocalic change that we cannot believe that it was motivated by any one of them.
The German facts are entirely analogous. Only later in the history of the language was the vocalic alternation made significant for number. And yet consider the following facts. The change of foti to föti antedated that of föti to föte, föt. This may be looked upon as a “lucky accident,” for if foti had become fote, fot before the -i had had the chance to exert a retroactive influence on the o, there would have been no difference between the singular and the plural. This would have been anomalous in Anglo-Saxon for a masculine noun. But was the sequence of phonetic changes an “accident”? Consider two further facts. All the Germanic languages were familiar with vocalic change as possessed of functional significance. Alternations like sing, sang, sung (Anglo-Saxon singan, sang, sungen) were ingrained in the linguistic consciousness. Further, the tendency toward the weakening of final syllables was very strong even then and had been manifesting itself in one way and another for centuries. I believe that these further facts help us to understand the actual sequence of phonetic changes. We may go so far as to say that the o (and u) could afford to stay the change to ö (and ü) until the destructive drift had advanced to the point where failure to modify the vowel would soon result in morphological embarrassment. At a certain moment the -i ending of the plural (and analogous endings with i in other formations) was felt to be too weak to quite bear its functional burden. The unconscious Anglo-Saxon mind, if I may be allowed a somewhat summary way of putting the complex facts, was glad of the opportunity afforded by certain individual variations, until then automatically canceled out, to have some share of the burden thrown on them. These particular variations won through because they so beautifully allowed the general phonetic drift to take its course without unsettling the morphological contours of the language. And the presence of symbolic variation (sing, sang, sung) acted as an attracting force on the rise of a new variation of similar character. All these factors were equally true of the German vocalic shift. Owing to the fact that the destructive phonetic drift was proceeding at a slower rate in German than in English, the preservative change of uo to üe (u to ü) did not need to set in until 300 years or more after the analogous English change. Nor did it. And this is to my mind a highly significant fact. Phonetic changes may sometimes be unconsciously encouraged in order to keep intact the psychological spaces between words and word forms. The general drift seizes upon those individual sound variations that help to preserve the morphological balance or to lead to the new balance that the language is striving for.
I would suggest, then, that phonetic change is compacted of at least three basic strands: (1) A general drift in one direction, concerning the nature of which we know almost nothing but which may be suspected to be of prevailingly dynamic character (tendencies, e.g., to greater or less stress, greater or less voicing of elements); (2) A readjusting tendency which aims to preserve or restore the fundamental phonetic pattern of the language; (3) A preservative tendency which sets in when a too serious morphological unsettlement is threatened by the main drift. I do not imagine for a moment that it is always possible to separate these strands or that this purely schematic statement does justice to the complex forces that guide the phonetic drift. The phonetic pattern of a language is not invariable, but it changes far less readily than the sounds that compose it. Every phonetic element that it possesses may change radically and yet the pattern remain unaffected. It would be absurd to claim that our present English pattern is identical with the old Indo-European one, yet it is impressive to note that even at this late day the English series of initial consonants:
| p | t | k |
| b | d | g |
| f | th | h |
corresponds point for point to the Sanskrit series:
| b | d | g |
| bh | dh | gh |
| p | t | k |
The relation between phonetic pattern and individual sound is roughly parallel to that which obtains between the morphologic type of a language and one of its specific morphological features. Both phonetic pattern and fundamental type are exceedingly conservative, all superficial appearances to the contrary notwithstanding. Which is more so we cannot say. I suspect that they hang together in a way that we cannot at present quite understand.
If all the phonetic changes brought about by the phonetic drift were allowed to stand, it is probable that most languages would present such irregularities of morphological contour as to lose touch with their formal ground-plan. Sound changes work mechanically. Hence they are likely to affect a whole morphological group here—this does not matter—, only part of a morphological group there—and this may be disturbing. Thus, the old Anglo-Saxon paradigm:
| Sing. | Plur. | |
|---|---|---|
| N. Ac. | fot | fet (older foti) |
| G. | fotes | fota |
| D. | fet (older foti) | fotum |