Some of these arise from the umlaut or epenthesis which is so prevalent, and which we have already seen in airya- as compared with the Skt.
Thus, taking the vowels alone; e = a by the principle .of umlaut.
umlaut facet object.
Recently I've used the character Ã¶, that is o umlaut.
Purchases Direct faxes from the German keyboard had the French circumflex instead of the German umlaut (Item 3).