[lxgr]

Sorting lists alphabetically would produce vastly different results by language, for one thing.

[wat10000]

Already a thing for some languages. For example, Hawaiian sorts its letters as A, E, I, O, U, H, K, L, M, N, P, W.

[jval43]

Collation rules already differ by locale or language in many programming languages, libraries, and applications.

This is necessary because the order of words or characters is sometimes only sensibly defined if you know the language a text is written in.