The Lambert shader adds a fake translucency effect to a surface, you can plug a shader into it, select 'use original colour' to then apply translucency to whatever the input node is. It also works as a child layer to a surface, while retaining the original colour of the parent layer too. it won't make it reflective but is good if used in combination with reflectivity, to make ice, or other semi opaque translucent crystals, perhaps.
To take away lots of render time from reflective shader rendering, uncheck 'ray traced reflections' in the shader's settings, this will result in a plain, specular highlight only type surface and it won't actually 'mirror' other parts of the scene in the reflectivity, this makes for a much faster to render reflectivity.