the resulting formal types (e.g., _Fuss_: _Fuesse_;
_fallen_ "to fall": _faellen_ "to fell"; _Horn_ "horn": _Gehoerne_ "group
of horns"; _Haus_ "house": _Haeuslein_ "little house") could keep
themselves intact and even extend to forms that did not legitimately
come within their sphere of influence. "Umlaut" is still a very live
symbolic process in German, possibly more alive to-day than in medieval
times. Such analogical plurals as _Baum_ "tree": _Baeume_ (contrast
Middle High German _boum_: _boume_) and derivatives as _lachen_ "to
laugh": _Gelaechter_ "laughter" (contrast Middle High German _gelach_)
show that vocalic mutation has won through to the status of a productive
morphologic process. Some of the dialects have even gone further than
standard German, at least in certain respects. In Yiddish,[162] for
instance, "umlaut" plurals have been formed where there are no Middle
High German prototypes or modern literary parallels, e.g., _tog_ "day":
_teg_ "days" (but German _Tag_: _Tage_) on the analogy of _gast_
"guest": _gest_ "guests" (German _Gast_: _Gaeste_), _shuch_[163] "shoe":
_shich_ "shoes" (but German _Schuh_: _Schuhe_) on the analogy of _fus_
"foot": _fis_ "feet." It is possible that "umlaut" will run its course
and cease to operate as a live functional process in German, but that
time is still distant. Meanwhile all consciousness of the merely
phonetic nature of "umlaut" vanished centuries ago. It is now a strictly
morphological process, not in the least a mechanical phonetic
adjustment. We have in it a splendid example of how a simple phonetic
law, meaningless in itself, may eventually color or transform large
reaches of the morphology of a language.

[Footnote 162: Isolated from other German dialects in the late fifteenth
and early sixteenth centuries. It is therefore a good test for gauging
the strength of the tendency to "umlaut," particularly as it has
developed a strong drift towards analytic methods.]

[Footnote 163: _Ch_ as in German _Buch_.]

IX

HOW LANGUAGES INFLUENCE EACH OTHER

Languages, like cultures, are rarely sufficient unto themselves. The
necessities of intercourse bring the speakers of one language into
direct or indirect contact with those of neighboring or culturally
dominant languages. The intercourse may be friendly or hostile. It may
move on the humdrum plane of business and trade relations or it may
consist of a borrowing or interchange of spiritual goods--art, science