Thanks for your imput.
See also: Metal umlaut
The umlaut diacritic can be used in "sensational spellings" or foreign branding, for example in advertising, or for other special effects. Häagen-Dazs is an example of such usage.
As the German short /a/ is more open than the equivalent sound in English (/ę/), Germans sometimes use the diacritic <ä> to imitate the English sound in writing, giving an English "feel" to words used in advertising; in a McDonald's restaurant in Germany one can buy a "Big Mäc".
Since the letter ü is very common in Turkish, its inappropriate use can make a text in another language look "turkified", a purely visual mimicry. Because of the large number of Turks living in Germany, this again is a phenomenon familiar in German. The Turkish-German satirist Osman Engin, for example, wrote a book entitled Dütschlünd, Dütschlünd übür üllüs - the opening line of the first stanza from Das Lied der Deutschen, but turkified.
In the heavy metal scene, the umlaut diacritic can frequently be observed as a mere decoration (with no significance for the pronunciation) on the names of bands such as Blue Öyster Cult, Motörhead, Mötley Crüe, Mägo de Oz, Queensr˙che, or Leftöver Crack. The group Spın̈al Tap places an umlaut over the <n>. A self-referential example is the Finnish group Ümlaut.