Evidentiality and language contact

[Extract] If a number of languages are in contact, with many speakers of one language having some knowledge of the other, then they typically borrow linguistic elements back and forth? habits of pronunciation, phonemes, grammatical categories, vocabulary items, and even some grammatical forms. Borrowing may extend over all or most of the languages in a geo?graphical region. We then get large-scale linguistic diffusion, defining the region as a ’lin?guistic area’. Languages in contact tend to converge: we find similar meanings obligatorily expressed, and parallel structures developed.1