Levelt, Willem J. M. Language Production Group Levelt, MPI for Psycholinguistics, Max Planck Society;
Levelt_On_Learnability_1990.pdf (Publisher version), 905KB
Levelt, W. J. M. (1990). On learnability, empirical foundations, and naturalness [Commentary on Hanson & Burr]. Behavioral and Brain Sciences, 13(3), 501. doi:10.1017/S0140525X00079887.