Code:

             var

              OriginalWordBreakProc : pointer;

              NewWordBreakProc : pointer;

            function MyWordBreakProc(LPTSTR  : pchar;

                                     ichCurrent : integer;

                                     cch : integer;

                                     code  : integer) : integer

               {$IFDEF WIN32} stdcall; {$ELSE} ; export; {$ENDIF}

            begin

              result :=  0;

            end;

            procedure TForm1.FormCreate(Sender: TObject);

            begin

              OriginalWordBreakProc := Pointer(

                SendMessage(Memo1.Handle,

                            EM_GETWORDBREAKPROC,

                            0,

                            0));

             {$IFDEF WIN32}

              NewWordBreakProc := @MyWordBreakProc;

             {$ELSE}

               NewWordBreakProc := MakeProcInstance(@MyWordBreakProc,

                                                    hInstance);

             {$ENDIF}

              SendMessage(Memo1.Handle,

                          EM_SETWORDBREAKPROC,

                          0,

                          longint(NewWordBreakProc));

            end;

            procedure TForm1.FormDestroy(Sender: TObject);

            begin

              SendMessage(Memo1.Handle,

                          EM_SETWORDBREAKPROC,

                          0,

                          longint(@OriginalWordBreakProc));

             {$IFNDEF WIN32}

               FreeProcInstance(NewWordBreakProc);

             {$ENDIF}

            end;