¿Qué relación hay entre el cambio lingüístico y la evolución del lenguaje?

The relation between language change and language evolution can be understood in two ways: according to the first one, both processes are independent; according to the second one, language change is a main factor in the evolution of the human faculty of language. Both options are correlated with different conceptions of language, and with different theories of language change. By examining so-called grammaticalisation theory, I analyse the arguments of both options and I conclude that the assumption that linguistic changes are relevant in the evolution of the human language faculty presents empirical and theoretical problems that make it unsustainable, and it hinders a proper understanding of both linguistic change and language evolution.