Solved , this is a way to set index marks in a voice dispatcher:
pthread_mutex_lock( m_connection->ssip_mutex );
spd_execute_command_wo_mutex( m_connection, "SET SELF SSML_MODE on" );
spd_execute_command_wo_mutex( m_connection, "SPEAK" );
char * reply = spd_send_data_wo_mutex( m_connection, "<speak>Hello, <mark name=\"mark1\"/> how does it work?</speak>", SPD_NO_REPLY );
delete[] reply;
spd_execute_command_wo_mutex( m_connection, "\r\n." );
spd_execute_command_wo_mutex( m_connection, "SET SELF SSML_MODE off" );
pthread_mutex_unlock( m_connection->ssip_mutex );
<mark name=\"mark1\"/> - . mark1 - .
: http://cvs.freebsoft.org/doc/speechd/ssip.html#Top