Neutron scattering of cold neutrons from liquid silane at 137° K and 98°K is explained on the basis of a simple model. The rotational diffusion constant,D_r, and the delay time,τ₀, after which rotational diffusion may be said to occur are derived on the basis of this model. At 137° K we getD_r=0.22×10¹³ sec⁻¹ andτ₀=0.68×10⁻¹³ sec. At 98°KD_r (=0.06×10¹³ sec⁻¹) is down by a factor of more than three butτ₀=(0.54×10⁻¹³ sec) shows only a small change. By comparison with data on liquid CH₄ it is concluded that the law of corresponding states is not applicable for describing rotational dynamics of CH₄ and SiH₄. Rotational motions in SiH₄ are more hindered than in CH₄ at the same reduced temperature.