VOWEL CHANGES IN INFLECTION AND WORD FORMATION.
147. The Dano-Norwegian language employs two most important kinds of vowel changes, which the Danish and Norwegian grammarians call “Aflyd” and “Omlyd”, in English generally called “gradation” and “mutation”.
148. By gradation (Aflyd, ablaut) we understand that system of the language enabling it out of the same root to form several stems by using different vowels; this principle is of great importance in the inflection of the verbs, but it also plays an important part in word formation; Ex.: bære to bear, bar bore, baaren borne, binde to bind, bandt bound, Baand ribbon, Bundt bunch, tage take, tog took.
149. By mutation (Omlyd, umlaut) is understood the change of a vowel caused by assimilation to a following vowel (i, u) or consonant (j). The sound causing the change has in the present language as a rule disappeared, but it is shown by a comparison with the earlier stages of the language. The principle of mutation is active both in inflection and in word formation. The u-umlaut is now in inflection found only in the word Barn child, plur. Börn.
By the i-umlaut the following changes are caused:
a—æ: Fader father, plur. Fædre, falde to fall, fælde to fell.
aa—æ: Haand hand, plur. Hænder.
o—ø: Moder mother, plur. Mødre, Blod blood, bløde to bleed.
u—y: tung heavy, comp. tyngre, huld gracious, hylde to swear allegiance to.
Note. In the i-umlaut it is a following front sound that influences (palatalizes) a preceding back sound.
