Like English and Italian, each of which have elaborate rules for forming words and sentences, so sign languages have rules for individual signs and signed sentences.

(A) Like English and Italian, each of which have elaborate rules for forming
(B) Similar to the elaborate rules that English and Italian have to form
(C) Just as English and Italian have elaborate rules for forming
(D) As with English and Italian, both having elaborate rules to form
(E) In the same way that there are elaborate rules used to form English and Italian

[spoiler]OA: Later[/spoiler]