From the linked page: "Slovio is not very Slavic at all: its grammar is almost entirely based on Esperanto, its word building mechanisms are mostly Germanic, a

From the linked page: "Slovio is not very Slavic at all: its grammar is almost entirely based on Esperanto, its word building mechanisms are mostly Germanic, and its vocabulary, although clearly dominated by (often mutilated) Russian words, does not relate in any predictable way to the Slavic languages either. As a result, its educational value is practically zero." This was also my impression of Slovio after attempting to read a few texts. Interslavic feels much more natural, coming from the perspective of a heavy dialect speaker of one of the south Slavic languages.