The following macro is present in mkii but obviously missing in mkiv. Why? 
I have a use for it.

ConTeXt  ver: 2010.03.20 22:59 MKIV  fmt: 2010.3.21  int: english/english
! Undefined control sequence.
l.184 \startlanguagespecifics
                             [nl]

In mkii in lang-spe.mkii
\def\startlanguagespecifics%                % we use double to
  {\bgroup ... \dodoubleempty\dostartlanguagespecifics} % get rid of spaces

Hans van der Meer