What is meant by &quot;rules&quot; is, of course, dependant on the definition, but in the field of SLA (second-language acquisition), &quot;rules&quot; are commonly understood to be like rules presented in language classrooms, and separate from &quot;some kind of internal systematic (implicit) knowledge of language&quot;.<p>What&#x27;s the role of rules in language acquisition is being debated. Check this essay Against &quot;rules&quot; by SLA researchers Jason Rothman and Bill VanPatten.<p><a href="https:&#x2F;&#x2F;www.researchgate.net&#x2F;publication&#x2F;263791085_Against_rules" rel="nofollow">https:&#x2F;&#x2F;www.researchgate.net&#x2F;publication&#x2F;263791085_Against_r...</a><p>EDIT: This non-expert article by the same author is more approachable: <a href="https:&#x2F;&#x2F;www.actfl.org&#x2F;sites&#x2F;default&#x2F;files&#x2F;images&#x2F;TLE&#x2F;TLE_OctNov14_Article.pdf" rel="nofollow">https:&#x2F;&#x2F;www.actfl.org&#x2F;sites&#x2F;default&#x2F;files&#x2F;images&#x2F;TLE&#x2F;TLE_Oct...</a>