\DeclareLanguage{arabic}

\SetLanguageScript{Ar}

\DeclareLanguageProperty{input = latin} 
  {\def\ara@input{7arb2uni}}

\def\ara@input{}

\AddLanguageProcess{transcript}{\ara@input}

\AddLanguageProcess{text}{uni2cuni}

% \DeclareLanguageCommand{\@hangfrom}{tools}[1]{%
%    \setbox\@tempboxa\hbox dir TRT{{#1}}%
%    \hangindent-\wd\@tempboxa
%    \noindent\box\@tempboxa}