The Peopling of the Canary Islands by Roger Blench (English Version)

Frankly, the linguistic materials used by the author in his study (Wölfel, 1965; Vycichl, 1952) are completely out of date (cf. Díaz Alayón, Reyes García). Historical and linguistic studies of Guanche materials have evolved greatly in quality and quantity from the late 1990s to the present day. The linguistic barrier of this knowledge (in this case in Spanish) can never be considered an obstacle for a researcher who intends to disseminate in a rigorous way. I have read the bibliography, mostly in English (genetics and archaeology), very few articles in Spanish, and those that exist do not deal with the linguistic question and date from the 1990s. I wonder what is a reasonable explanation for this.