'Roots music'? Most of the music marketed under the 'World' label is not foundation music, but contemporary and fusion. A minute part is roots music from a 'certain' culture since all cultures today are mixed. Except in a historical context, 'roots music' is meaningless.
The online "RootsWorld" negates its title by reviewing and discussing music that is the result of "cross-cultural pollination"- true of almost all current music.

Looking at Hawaiian music (trying to get a somewhat isolated region), as 'roots' music we may have a few hulas and chants of pre-European type, but the music quickly developed far beyond that, adding, to the Polynesian-East Asian base, elements first from European and American sources but now containing African and Caribbean influences (e. g., reggae- which is American Indian, European and African 'fusion').

'World Music' is used mostly in Europe, but is frequently heard in American marketing as well, to group "the many genres of non-western music which were previously described as "folk music" or "ethnic music," succinctly described as "music from out there." (Wikipedia, my least favorite reference, but, in this case, usable). The BBC has developed categories and awards for World Music.

Almost none is intrinsically 'roots' music, a form having interest more to music historians than to contemporary musicians, regardless of their ancestry or geographical situation.

The big American marketers use terms like 'international' (with subcategories ,including zydeco, Latin, Mexico, Celtic, Far East and Asia, reggae, etc., some usable and some hopeless). The BBC classification makes more sense.