This topic should be renamed to "Specification and Description Language" as this is the proper expansion of the acronym SDL, when it refers to ITU-T Z.100. Moreover, SDL is now used to mean "System Design Language(s)" as usage changed somewhat over the years, so that SDL covers using the ITU-T Z.100 language with other ITU-T languages such as ASN.1, MSC and TTCN.
I agree. Thus I have swapped the content of "Specification and Description Language" and "Specifciation and Design Language" MJ 19. 12. 2006 "Specifciation and Design Language" now redirects to "Specification and Description Language". I think SDL refered at beginning to the term "Specifciation and Design Language", if this is the case, please make a note on the "Specification and Description Language" page.