A metaplasm[1] is almost any kind of alteration, whether intentional or unintentional, in the pronunciation or the orthography of a word.[2] The change may be phonetic only, such as pronouncing Mississippi as Missippi in English, or acceptance of a new word structure, such as the transformation from calidus in Latin to caldo (hot) in Italian. Orthographic metaplasms have been used in philosophy to advance humanity's conceptual terrain, such as when Derrida adapted Heidegger's Destruktion into deconstruction or the French term différence into différance. Changes at either level may or may not be recognized in standard spelling, depending on the orthographic traditions of the language in question. Originally the term referred to techniques used in Ancient Greek and Latin poetry, or processes in those languages' grammar.
Many phonological changes found frequently in the natural development of languages are metaplasms:
In rhetoric, metaplasm is the modification of word order for emphasis.
In the grammar of the Romance languages, metaplasm may refer to change in the grammatical gender of nouns from their original gender in Latin.