(1) A vowel whose quality or length is changed to indicate linguistic distinctions (such as sing sang sung song
(2) A vowel whose quality or length is changed to indicate linguistic distinctions (such as sing sang sung song)
(1) When ablaut is a regular feature of a language's grammar, it is often called vowel gradation.
(2) It is the relationship between phonemic pitch and the nature of ablaut in standard Lithuanian which makes this clear.
(3) There are various categories of this: rhyming, exact and ablaut (vowel substitution).
(4) An ablaut series
(5) The Proto-Indo-European phonetics was not stable at all: ablauts (vowel interchanges), assimilations, many different consonant processes at the end of the word.
(6) You can't even distinguish between the preterite and participle Germanic ablauts of English.