This　paper　presents　a　Chinese　sign　language/spoken　language　dialog　system　based　on　the　technique　of　large　vocabulary　continuous　Chinese　sign　language　recognition　(SLR)　and　Chinese　sign　language　synthesis　(SLS),　which　is　new　development　for　HandTalker.　In　the　SLR　module,　a　fuzzy　decision　tree　with　heterogeneous　classifiers　is　presented　for　large　vocabulary　singer-independent　SLR,　and　then　large　vocabulary　continuous　SLR　based　on　transition　movement　models　is　proposed.　In　SLS　module,　three　key　techniques:　realistic　3D　facial　animation　and　gesture　retargeting　technique　and　synchronization　modal　on　gesture　and　lip　motion　are　employed　to　improve　sign　language　synthesis　vividness.　©　2004　IEEE.