Types+of+Language+Changes--Vocabulary

Define, with meaningful examples, the following types of language change:
 * ablaut gradation
 * analogy
 * apheresis
 * aphesis
 * apocope
 * assimilation
 * dissimilation
 * ellipsis
 * epenthesis (svarabhakti)
 * metathesis
 * rhoticism (aka rhotacism)
 * stress shift
 * syncope
 * umlaut (mutation)
 * i-mutation (aka j-mutation)
 * borrowing
 * compounding
 * coining of new words
 * acronyms
 * portmanteau
 * back formation
 * euphemism
 * folk etymology
 * metonymy
 * synecdoche
 * learned (etymological) respelling
 * phonetic spelling
 * hypercorrection
 * folk etymology
 * semantic broadening
 * semantic narrowing
 * amelioration
 * pejoration