If you want change specular light to a softer, more diffused type of light, you should use a diffuser. Diffusers are usually made of translucent or mesh materials. When you place them in front of the light source they will break up or soften and diffuse the light beam. If you want the light to be diffused more, you should use a finer mesh or two pieces of mesh or screen placed together and slightly out of alignment. If you don't want too much diffusion you should use a wider mesh material.
Diffusers may be attached on your light source unit or positioned between the light and your subject. Some lamps give off diffused light, but if you don't have one handy a diffuser will do the job. Diffusers come in various types, styles, shapes, colors and materials. Diffusers often come in kits with other lighting accessories or can be bought separately for a few dollars.