Complex sentence: In fact "lay" derives from a causative of the verb from which "lie" derives; the two verbs are sometimes confused, with "lay" being used in the intransitive senses which prescriptively are reserved for "lie".
Split into simpler sentences: In fact "lay" derives from a causative of the verb from which "lie" derives. The two verbs are sometimes confused, with "lay" used in the intransitive senses prescriptively reserved for "lie".