\defineframed
  [myframe]
  [foregroundstyle=italic,
   foregroundcolor=blue]

\def\mycmd#1{\color[blue]{\strut#1}}

\starttext

  \processisolatedwords{three four}\mycmd

  \processisolatedwords{five six}\myframe

  \applytowords\mycmd  {seven eight}

  \applytowords\myframe{nine ten}

  \applytosplitstringchar      \myframe{eleven twelve}\par
  \applytosplitstringword      \myframe{eleven twelve}\par
  \applytosplitstringline      \myframe{eleven twelve}\par
  \applytosplitstringcharspaced\myframe{eleven twelve}\par
  \applytosplitstringwordspaced\myframe{eleven twelve}\par
  \applytosplitstringlinespaced\myframe{eleven twelve}\par

\stoptext
