Many Minmatar still speak Amarish as their first language, even more so since the return of the Nefantar and Starkmanir, and "Republic Matari" is considered an unsatisfactory reconstruction of the common language of the old Minmatar Empire. All tribes are concerned to address this cultural issue and wish to live and speak according to their true heritage.
(Though the suggestion from the Krusual that all Minmatar adopt their tribal language, which remains almost entirely intact due to the Krusual resistance, was politely declined by the other tribes when the Republic was founded.)
Due to these concerns, major efforts are underway within the Republic to recover what is possible of all historical tribal languages and dialects, so as to restore them for use in modern Minmatar tribal societies. This calendar comes from an industry born out of that sentiment. There's a new Matari word for each of the 1357 days of the Matar year!