. Systems Research Laboratories, NEC Corporation 1-1, Miyazaki 4-chome, Miyamae-ku, Kawasaki City, Kanagawa 213, Japan (fuku@tsl.cl.nec.co.jp, ohyama~tsl.cl.nec.co.jp,. more labo- rious for Japanese and several other languages, which have no explicit word boundaries, than for Engllsh and many European languages (Miyazald,...