How can I speak more clearly if I have a lisp?

The big thing is looking at your oral motor and the function of the mouth and making sure that the positioning is appropriate. It's a little harder when it's a very specific sound like ‘S’ because you have to also look at how the tongue is being placed. Each sound that we make is done in a certain way with certain positioning. Some sounds can be made in multiple ways. However, if you aren't placing these things appropriately, what we call our articulators – your tongue, your lips, your mouth, even your teeth, and different things within the oral cavity – you in turn can get some sounds that might not sound appropriate or might sound atypical, and that's how lisping comes about. Speaking more clearly takes a lot of repeated practice. It's modeling. Using a mirror as a reference point is helpful. There are some good applications out there that can give that imagery of somebody producing an ‘S’ in a way that is more effective or appropriate and tends to reduce that lisping. Of course, the best thing to do if it's going on for a longer period of time and past the point of what is typical, is to seek out services from a speech therapist.