Umlaut
Part of speech: verb
Definition: To place an umlaut over a vowel.
Part of speech: noun
Definition: An assimilatory process whereby a vowel is pronounced more like a following vocoid that is separated by one or more consonants. The umlaut process (as above) that occurred historically in Germanic languages whereby back vowels became front vowels when followed by syllable containing a front vocoid (e.g. Germanic lūsi > Old English līs(i) > Modern English lice). A vowel so assimilated. The diacritical mark ( ¨ ) placed over a vowel to indicate such assimilation.
Diaeresis
Part of speech: noun
Definition: A diacritic placed over a vowel letter indicating that it is sounded separately, usually forming a distinct syllable, as in , , .The separation of a vowel, often a diphthong, into two distinct syllables.A natural break in rhythm when a word ends at the end of a metrical foot, in a line of verse.