Does Paris Hilton have a “lisp” to you? She seems to really attack those s’s but I wouldn’t call it a lisp. But maybe the OP does.
The lead singer from Modest Mouse (you’ll recognize his band from Rock Band!) has a lisp. I always sang along to their songs with a lisp but always just thought it was a flair in the way he sang. Not so…it’s real. And I’m obsessed with it.
Interesting note. Had some time at lunch to catch up on this thread and find a SJP example. So before I started looking, I clicked on the example provided upthread… Sure enough, I didn’t hear much of a lisp either in that. It may be because she has a piece of gum in her mouth while she is giving the interview, I don’t know.
I’ll find one. I just need to find a decent SATC clip on youTube.
Interestingly, I did a quick Google search, and THIScame up as the first result. So apparently, in 2006, doper Wile E thought she had a lisp, also.
I also read another link from the google that said her lisp is fake. I don’t know if that’s true or not. I can tell you that I heard her on SATC and she lisped constantly, so I shouldn’t have a problem finding something. I’ll search tonight.
It would serve me right if my biggest gripe is with someone who faked it for her character on SATC!
I don’t think Paris Hilton has a lisp, but as you say, she really attacks the s’s. It’s close, but I’d say no. But then again, I’m partial to her, so maybe I’m just being biased. 
I’m vaguely remembering a discussion we had in a sociolinguistics class I took. It was about the alternation between the “pure” s sound and the sh sound. This is not a lisp, it’s a learned phonemic variation. People who use the “sh” version of the sibilant will use it most noticeably at the beginning of a second consecutive s-word; for example, “State Street” would sound like “State Shtreet”. People who do this will put a little bit of sh in all of their s-es, though. People who don’t do this can hear it clearly if they listen.
IIRC, and no I don’t have any cites, this tendency varies first by region and second by generation within the region, just like the New England tendency to add -r to the end of words that end with vowels varies from generation to generation.
So if this is what you’re hearing, then yeah, there is a generational component to it.
It’s Don Mattingly who won’t get rid of those damn sideburns. SJP has gigantism from drinking too much nerve tonic.
Rudy Giuliani comes to mind when I think of famous adults who have a lisp. I don’t run into too many adults who have a lisp. People still send children to speech therapists to get rid of lisps.
Mo Rocca has a very noticeable one, but he does manage to compensate for the sounds that would otherwise be very Daffy Duck, if he didn’t control it somewhat. But he is clearly using his tongue in the conventional teeth-lisp manner.
Lisping - has it taken over as “normal” speech?
Other than in Spain, no, not that I can tell.
A division manager I worked under until the end of March lisps. Bit distracting when she led meetings.
OK. I admit I didn’t search long, but I wanted to find something that you didn’t need to watch through for 5-10 minutes to get to see what I’m referring to.
First, listen to Carrie’s narration, and you can hear her hard “s” sounds. Sounds like a bit of air coming out of a tire every time she hits one.
Her first line, she says “miss” (as in miss you). Watch and listen to this. Her tongue goes on the back of her teeth and she pushes the “s” sound out. This is what I am talking about. It’s staying on the “s” longer than required in normal speech. If we can SJP, I’ll add two to make it more understandable.
Drew Barrymore (as mentioned before) clearly uses her tongue too much when she makes the “s” sound.
Michele Obama has a very bad lisp (not to mention an under bite of epic proportions).
Dan Dierdorf - HERE
These aren’t Cindy Brady lisps, where you see the tongue… these are lisps where the speaker has uses his tongue to push against the inside front of their teeth to make the “s” sound.
I know this may sound like nitpiking, but the question remains. When I was a kid, and you spoke with a lisp, you were usually sent to a speech therapist who taught you how to speak without one. Therefore, most people I graduated with did not lisp. Now, it seems that the majority of kids and young adults I’ve heard speak have a lisp of some level or another.
Mo Rocca is an excellent example! Very strong lisper.
There are so many out there, sometimes I can’t think of the best examples.
Feel free to add names and examples to this thread if you know what I’m talking about.
I’m still not hearing it. Maybe you’ve got a hearing disorder! 
Wow, I definitely hear the lisp there. It’s mind boggling I never noticed it before you pointed it out!
There’s also Christopher Mintz-Plasse who played Mclovin in Superbad, and the Red Mist in Kick-Ass.
I’ve noticed it too. It’s only mild lisping, not thee thellth theathellth on the theethore, so if that’s what people are listening for then they won’t hear it. The speaker doesn’t move their tongue towards the roof of their mouth as much as people usually do with an s. The same softening happens with other letters, like l and t (at the beginning of words).
It’s hard to think of examples for something that’s so mild but nonetheless fairly common.
Almost every American pre-teen I hear on TV or in the movies has a lisp, whereas it’s really rare in real life in the UK above the age of four or so. Dakota Fanning narrating Spielberg’s Taken, for example.
What about Rosie Pope? Does she have a lisp or speech impediment or is that her accent. It’s hard to watch her show because of the accent or whatever that is.
The one that comes to mind for me is Dante Basco as Zuko in Avatar TLA.
Ah, that’s sibilance. She’s hissy, not lispy. I’m wondering if that wasn’t a put-on for the character.
I’ve heard it fairly often in the U.K.
From what I’ve seen its an affectation by kids acting cute for their parents, most parents tell them to stop acting like big babies and the kids drop the habit.
However some parents still think of their offspring as cute little babies long after the appropriate age, don’t pull the kids on it and the affectation becomes an engrained habit in adulthood that they genuinely can’t help.
(Though I wouldn’t be stunned with amazement if they secretly thought that it still made them sound cute)
My 5-year-old son lisps. I don’t think he can help it. He simply can’t seem to pronounce “S” without a little “Th” in it. Oh, well. I’m certainly not going to punish or mock him for something he can’t help. No one else in the house lisps, including my two-year-old daughter, so it’s not something we encourage.
The only other people I can remember lisping is Spanish speakers from certain parts of Spain. Drives me batshit since I learned Spanish in Chile (it just sounds really pretentious to my ear, even though I know it’s a dialect, not an attitude - for most anyway). I get all stabby when I hear “Ibitha,” but that’s how you pronounce it there, so that’s that.
This is exactly what I was wondering: does the OP define a lisp as any difference in the production of sibilant consonants? In that case, I’d agree that it’s much less of a big deal. But actual lisping? No, it is not accepted.