Juan Ignacio María Aizpitarte Muguerza (Elgoibar, Gipuzkoa, October 12, 1750 – Vitoria-Gasteiz, August 4, 1809) was a Basque lexicographer and a prominent representative of Basque linguistic Enlightenment at the end of the 18th century.
He was born in Elgoibar in a context where Basque coexisted with Spanish and Latin as languages of culture. His intellectual trajectory developed within the framework of Enlightenment thought, characterized by an interest in the documentation, study, and atization of vernacular languages.
He is primarily recognized for his lexicographical work, focused on the study and compilation of Basque vocabulary. Commissioned by the Count of Peñaflorida, he composed a dictionary intended to correct the omissions and deficiencies of the one published by Larramendi. In 1774, he presented to the Royal Basque Society of Friends of the Country a collection of 388 folios in alphabetical order, which was later used by Aizkibel for the preparation of his own dictionary. This manuscript has been preserved since 1883 in the Jesuit library in Loiola.
Aizpitarte Muguerza married Francisca de Maguregui on April 4, 1771. His figure represents a convergence Enlightenment culture and Basque tradition, at a time of growing concern for the preservation and description of the Basque language. Although few details are known about his daily life, his lexicographical contribution is considered pioneering in the reflection and atic organization of Basque vocabulary.
He died in Vitoria-Gasteiz on August 4, 1809, leaving a legacy that links Enlightenment scholarship with the early history of Basque language codification.