German Ui (Uibel, Uiber- in compounds or derivations) is commonly an alternative form of Ue or Ü, and it's very rarely used in lower case as ui.
Maybe Ui was used by some as it better fits to the vowel sound of the letter ü (the sounds represented by the letters u, i, ü are more close than the sounds represented by e, ä, a); while others used Ue like it's Ae, Oe and sometimes aͤ, uͤ, uͤ.
- C. Edler, Die deutsche Sprachbildung, nach ihrem gegenwärtigen Standpunkte und mit Rücksicht auf ihre mögliche fernere Gestaltung. Erster Theil. Die Begriffe und ihre Formen, Leipzig, 1847, p. 3: "Indessen dürfte unzweifelhaft sein, daß unser ü zweifacher Natur ist, einmal als Umlaut des u, z. B. in: Brüder aus Bruder, sodann als Schleifung aus u und i. Der letztere Charakter wird jedoch nur dann bemerklicher, wenn der Laut allein eine Sylbe bildet, wie in über, Uebel, welche Wörter man in früherer Zeit daher auch uiber und Uibel zu schreiben pflegte, was nicht bei Brüder geschah, wo die Umlautung des u zu Tage liegt. Auch in hui! und pfui! ist ui noch vorhanden."
Meanwhile it may be without doubt that our (that is, the German) ü is of twofold nature, first as the umlaut of u (i.e. in Brüder from Bruder), and then as a blend of u and i. The latter sound, however, only becomes more noticeable when it forms a separate syllable, as in über, Uebel, which in earlier times were also written as uiber and Uibel, but which is not the case with Brüder, where the ü is the umlaut of u'. Also in hui and pfui the ui is still present.
— Nowadays in High or Standard German pronunciation, ü in Brüder is [yː] in IPA, and ü in über is [ˈyː] (with stress mark), while ui in hui is a rare diphthong [ʊɪ̯]. Maybe the author mentioned a dialectal difference between two types of ü, or made some kind of pseudo-distinction as once was sometimes done for f vs. v (für, Fuchs vs. von, Vogel).
- Swabian is said to have a diphthong ui (as in the German interjection hui). That could explain Edler's explanation, if he was from Swabia or lived there. But that wouldn't explain Ui (or ui?) in a text from a non-Swabian person.
- J. B. Fr. Weyh, Praktisches Handwörterbuch des Deutschen Sprachgebrauchs. Zweite Ausgabe, 1843, Regensburg, has "übel" but "Uibel", "übertreiben" but "Uibertreiber", yet it has "ärgern" and "ägerlich" and "Aerger" — There Ui is an alternative form of Ue or Ü (i.e. it should be without ui except in interjections and loans). Its often similar in other texts, like with "Uiber die Tiroler" in the title but with "über" in the text.
- Searching for "uiber" and even "und uiber" at google, it's commonly "Uiber" in the results. Some exceptions with "uiber" (author, place, year): K. G. D. Manderbach, Frankfurt am Main, 1799; Wilhelm Rothammer, Regensburg, 1785; ?, ?, 1787 – Another kind of exceptions: "und uiber lant" (19th century print of Ulrich Boner's work, who lived in the 14th century), "und uiber die Soldaten" (could come from a chapter or paragraph title of another book, i.e. it could be Uiber mischanged to uiber), "Und uiber den achten [Tag] soll man..." (cite, said to be from some Alemannic law, so could be Swabian ui), "Gottes zorn uiber den kuinig und uiber die Luite" (MHG or dialect?).
-22.214.171.124 00:25, 25 June 2017 (UTC)