While the physically correct way would be diffuse and translucency mixed, with a lightsource inside, translucency creates indirect illumination which may take longer to get clean results from. Here is how I do this effect - in this case I’m using math nodes, but you could bake out the actual result and use images instead. That turns it into a direct light source which renders faster. You may want two textures; one for the inside and one for the outside.