I agree that this is a documentation bug, but there is an easy way to split on any isspace character:
julia> const spaces = filter(isspace, Char(0):Char(0x10FFFF)); julia> split("Time flies like an arrow.(光陰矢の如し)", spaces) 5-element Array{SubString{UTF8String},1}: "Time" "flies" "like" "an" "arrow.(光陰矢の如し)"