MORPHOLOGY: a term which is used for the class of verbs where inflection
is expressed by stem allomorphy or ablaut, that
is, by a change of the stem vowel, a change of the stem consonants, or both.
EXAMPLE: English: sing:sang:sung, dwell:dwelt:dwelt, and
bring:brought:brought, Dutch: loop:liep:gelopen, zit:zat:gezeten.