Then s and t are not present in any of the same languages, but there are two languages l i , l j ∈ L such that l i has character s but not t, and language l j has character t but not s. If s and t are only present within the language grouping, they are not informative when language family grouping is used.
if both s and t are present at an internal node ancestral to language grouping L, then this will make the data closer to admitting a CDP by decreasing the number of borrowings that we need to posit.