There is no definite answer to that. Clients differ. Some have more affinity for and experience with technical things and jargon and some dont. Some dig buzzwords, some prefer plain english. You have to adapt to the individual client. The most important thing is finding out together what they really need - not what they think they need. Or As Henry Ford put it:
"If I had asked people what they wanted, they would have said faster horses."
One of the biggest misconceptions I have come around regarding CMS is clients tend to underestimate the effort they have to put into it once they have it. They think (or have been told) a CMS is easy and cheap: you can update your content yourself and you dont have to pay the expensive agency to update your site anymore. Sounds brilliant, but it's a myth.
Clients have to understand that Content Management is a process that requires a lot of work. It's not just some technical thingie you install. That's only the smallest part. It also takes time to know the CMS and it takes practise. Use it or lose it. A CMS has to be used by someone and those people have to understand the aims of the website. They have to have a skillset in editing and writing and - if you allow extensive designing - design. Otherwise, the CMS a) wont be used and/or b) will contain poor content and/or c) look like crap.
Despite being six years old and published on April 1st, I find most of the arguments in Why Content Management Fails still very valid and good to consider when working with clients who want a CMS.