Editing Germanic umlaut (section)

=====Notes=====
#The phonologically expected umlaut of {{IPA|/a/}} is {{IPA|/æ/}}. However, in many cases {{IPA|/e/}} appears. Most {{IPA|/a/}} in Old English stem from earlier {{IPA|/æ/}} because of a change called [[a-restoration]]. This change was blocked when {{IPA|/i/}} or {{IPA|/j/}} followed, leaving {{IPA|/æ/}}, which subsequently mutated to {{IPA|/e/}}. For example, in the case of {{lang|ang|talu}} "tale" vs. {{lang|ang|tellan}} "to tell," the forms at one point in the early history of Old English were {{lang|ang|*tælu}} and {{lang|ang|*tælljan}}, respectively. A-restoration converted {{lang|ang|*tælu}} to {{lang|ang|talu}}, but left {{lang|ang|*tælljan}} alone, and it subsequently evolved to {{lang|ang|tellan}} by i-mutation. The same process "should" have led to {{lang|ang|*becþ}} instead of {{lang|ang|bæcþ}}. That is, the early forms were {{lang|ang|*bæcan}} and {{lang|ang|*bæciþ}}. A-restoration converted {{lang|ang|*bæcan}} to {{lang|ang|bacan}} but left alone {{lang|ang|*bæciþ}}, which would normally have evolved by umlaut to {{lang|ang|*becþ}}. In this case, however, once a-restoration took effect, {{lang|ang|*bæciþ}} was modified to {{lang|ang|*baciþ}} by analogy with {{lang|ang|bacan}}, and then later umlauted to {{lang|ang|bæcþ}}.
#A similar process resulted in the umlaut of {{IPA|/o/}} sometimes appearing as {{IPA|/e/}} and sometimes (usually, in fact) as {{IPA|/y/}}. In Old English, {{IPA|/o/}} generally stems from [[a-mutation]] of original {{IPA|/u/}}. A-mutation of {{IPA|/u/}} was blocked by a following {{IPA|/i/}} or {{IPA|/j/}}, which later triggered umlaut of the {{IPA|/u/}} to {{IPA|/y/}}, the reason for alternations between {{IPA|/o/}} and {{IPA|/y/}} being common. Umlaut of {{IPA|/o/}} to {{IPA|/e/}} occurs only when an original {{IPA|/u/}} was modified to {{IPA|/o/}} by analogy before umlaut took place. For example, {{lang|ang|dohtor}} comes from late [[Proto-Germanic]] {{lang|gem-x-proto|dohter}}, from earlier {{lang|gem-x-proto|duhter}}. The plural in Proto-Germanic was {{lang|gem-x-proto|duhtriz}}, with {{IPA|/u/}} unaffected by a-mutation due to the following {{IPA|/i/}}. At some point prior to i-mutation, the form {{lang|gem-x-proto|duhtriz}} was modified to {{lang|gem-x-proto|dohtriz}} by analogy with the singular form, which then allowed it to be umlauted to a form that resulted in {{lang|ang|dehter}}.

A few hundred years after i-umlaut began, another similar change called double umlaut occurred. It was triggered by an {{IPA|/i/}} or {{IPA|/j/}} in the third or fourth syllable of a word and mutated ''all'' previous vowels but worked only when the vowel directly preceding the {{IPA|/i/}} or {{IPA|/j/}} was {{IPA|/u/}}. This {{IPA|/u/}} typically appears as {{angbr|e}} in Old English or is deleted:

* {{lang|ang|hægtess}} "witch" < PGmc {{lang|gem-x-proto|hagatusjō}} (cf. [[Old High German]] {{lang|goh|hagazussa}})
* {{lang|ang|ǣmerge}} "embers" < Pre-OE {{lang|mis|*āmurja}} < PGmc {{lang|gem-x-proto|aimurjǭ}} (cf. Old High German {{lang|goh|eimurja}})
* {{lang|ang|ǣrende}} "errand" < PGmc {{lang|gem-x-proto|ǣrundijaz}} (cf. [[Old Saxon]] {{lang|osx|ārundi}})
* {{lang|ang|efstan}} "to hasten" < archaic {{lang|ang|øfestan}} < Pre-OE {{lang|mis|*ofustan}}
* {{lang|ang|ȳmest}} "upmost" < PGmc {{lang|gem-x-proto|uhumistaz}} (cf. [[Gothic language|Gothic]] {{lang|got-Latn|áuhumists}})

As shown by the examples, affected words typically had {{IPA|/u/}} in the second syllable and {{IPA|/a/}} in the first syllable. The {{IPA|/æ/}} developed too late to break to {{lang|ang|ea}} or to trigger palatalization of a preceding velar.