the differences in speech have been intensified by the lack of interaction. The literary tradition in the French Basque Country, especially in Labourd, has had great importance in the history of the Basque language. The first Basque writers on that side of the Pyrenees took the language from the Labourd coast as their base language for literature, more specifically the triangle formed by Ciboure, Sare, and Sainte-Jean-de-Luz. The language has evolved in the literary plane from classical Labourd dialect used by writers in the Sare School, to the literary Navarro-Lapurdian dialect, a sort of Basque unified in the French Basque Country made concrete by a grammar book by Pierres Lafitte Ithurralde in the 1940s. In many ways, it is considered one of the predecessors of Standard Basque, and it currently survives as an unrecognized version of unified Basque. In other words, it is a unified Basque with lexical and morphological elements unique to the region. The Navarro-Lapurdian dialect and Souletin have common characteristics that distinguish them from other Basque dialects, such as the pronunciation of (according to Koldo Mitxelena, it was lost around the 13th century in the Pyrenees territories due to Aragonese influence and became extinct on the Labourd coast around the 19th century, according to Louis Lucien Bonaparte), the differences in speech in the grammatical cases of (absolutive) and (ergative), and the use of the root * in front of * used in speech on the other side of the Bidasoa ( vs. ). The Royal Academy of the Basque Language took into account the four centuries of literary tradition of this region when it began the unification project. According to the theory of waves or gradients, the Souletin and Biscayan dialects are the dialects that have conserved the largest number of archaisms due to their geographical location, but at the same time, they had the greatest influence from other languages (Mitxelena). This is why Souletin is considered innovative with regards to its phonology (influenced mainly by Gascon), but conservative in its lexicon and morphology. Souletin relies on a written literary tradition of great importance, but something worth noting is the oral tradition, since ancient ballads and songs have been passed on from generation to generation up until current times, being rescued by musicians and singer-songwriters in the second half of the 20th century. The Soule people have a firm popular theatre tradition, and pastorals and masques reflect