There is a special imperative form for 2nd-person, but there is no difference between singular and plural. <br><br>For example, in English the form <i>Go!</i> without any overt subject is only allowed in the 2sg or 2pl imperative, but it is the same form for both. <br><br>On the other hand, Icelandic has a special form for the 2sg imperative, a stem plus a 2sg clitic as in <i>far-ðu</i> ‘go.stem-2sg.CL’, and a different form for the 2pl imperative, namely the stem of the verb with a 2pl agreement suffix and no overt subject, as in <i>far-ið</i> ‘go.stem-2pl.AGR’. Thus, Icelandic, unlike English, does not have a syncretic 2 person imperative form. 
<br><br><b>Reference</b><br>
van der Auwera, Johan & Lejeune, Ludo (with Pappuswamy, Umarani & Goussev, Valentin). 2008. The Morphological Imperative.
In Haspelmath et al. (2008), chapter 70.
Available online at <a href="http://wals.info/feature/70">http://wals.info/feature/70</a href>.