gradáció

Gradáció, in linguistics, is the systematic alternation of sounds within a word to express different grammatical or semantic categories. It is a form of morphophonological alternation and can involve changes to vowels (ablaut or vowel gradation) or to consonants (consonant gradation). The phenomenon is cross-linguistically widespread and often tied to inflection or derivation, rather than to the addition of new affixes alone.

Vowel gradation occurs when the stem vowels change to signal tense, aspect, mood, or other grammatical distinctions. A well-known example is found in English strong verbs, where the verb forms show internal vowel changes, such as sing, sang, sung. Consonant gradation, common in Finnic languages like Finnish and Estonian, involves changes to stem consonants across related forms, typically in inflected paradigms, and can interact with vowel changes or suffixal alterations.

Gradation serves several linguistic functions. It can encode grammatical information without increasing the number of morphemes, contribute to the formation of comparative or superlative degrees in some languages, or reflect historical sound changes that have become part of the modern inflectional system. In historical linguistics, gradation patterns are important clues for reconstructing proto-forms and tracking how inflectional systems develop over time.

Not all languages preserve gradation in the same way; in many languages it has become obscured or lost due to phonological leveling or the regularization of inflection. Nonetheless, gradation remains a fundamental concept in the study of morphophonology and word formation.

See also: ablaut, morphophonology, consonant gradation, vowel harmony.