Since some languages have (as @Someone Else 37 pointed out) diphthongs that English does not.
In Dutch "ei" is such a diphthong and so the umlaut above the ï is used to point out that the e and i should be pronounced separately and not as a diphthong.
What's with you suddenly being so picky about grammar, man?
In Dutch "ei" is such a diphthong and so the umlaut above the ï is used to point out that the e and i should be pronounced separately and not as a diphthong.
What's with you suddenly being so picky about grammar, man?