The concept of easy and difficult grammar rules has been defined on the basis of different perspectives, including psycholinguistic, linguistic, and pedagogical perspectives, and there has so far been little consensus on the definitions. Studies on the effects of different types of instruction on learning easy and difficult rules have also presented mixed results, which may be due to the lack of consistent definitions associated with these grammar rules. However, positive effects of explicit instruction in both easy and difficult grammar rules have often been reported. Pedagogical implications include techniques used in both explicit and implicit instruction and how to draw learners' attention to both levels of grammar rules during classroom activities, for example, through the effective use of corrective feedback, dictogloss, and languaging.
The abstract above is courtesy of Wiley-Blackwell.