\documentclass{minimal}
\listfiles
%\usepackage[T1]{fontenc}
%\usepackage[latin1]{inputenc}
\usepackage{pstricks,pst-jftree}
\pagestyle{empty}
\parindent=0pt

\begin{document}
\deftriangle\fixedtri(.8)(1)(-1)
\defbranch\steepmedleft(1)(2)
\defbranch\steepmedright(1)(-2) 
\def\overnode#1#2{%
  \vtop{\offinterlineskip 
    \halign{\hfil##\hfil\cr \vrule width0pt depth5pt #2\cr \pnode{#1}\cr}}} 
\jftree[xunit=54pt,yunit=22pt,triratio=.5,everynode={\strut}] 
\!\0{IP} 
  \fixedtri[triratio=.95]\1 
  \fixedtri{\triline{sono stati\hfil}}\cr 
\!\1{FP}\medleft\2\medright\3\cr 
\!\2{$F_{\rlap{$\scriptstyle[+strong]$}}$} 
  \medvert{\overnode{A1}{$arrestati_i$}}\cr 
\!\3{Voice$_{\rlap{$\scriptstyle Pass$}}$} 
  \medleft{\hskip1.4em\overnode{A2}{Voice}$_{Pass}$} 
  \medright\6\cr 
\!\6{$Agr_OP$}\medleft\7\medright\8\cr 
\!\7{DP}\medvar{\overnode{A3}{alcuni uomini$_m$}}\cr 
\!\8{${Agr_O}'$} 
  \steepmedleft{\overnode{A4}{$Agr_O$}} 
  \steepmedright\9\cr 
\!\9{VP}\medvar{\quad\overnode{A5}{${\mathit{t}}_{\,i}$} 
  \overnode{A6}{${\mathit{t}}_{\,m}$}\quad}\cr 
\endjftree 
{\psset{nodesepA=0,nodesepB=3pt,arrows=->} 
 \ncarc[arcangle=45,nodesepA=5pt]{A2}{A1} 
 \nccurve[angleA=-150,angleB=-70]{A5}{A4} 
 \nccurve[angleA=-140,angleB=-70,nodesepA=3pt, linestyle=dashed]{A6}{A3} 
 \nccurve[angleA=-160,angleB=-100,ncurv=1.4,nodesepA=5pt]{A4}{A2}} 

\end{document}
