yes, there is a way (several ways). Actually I have no espeak, so I cannot test it, but in general it should work:
#you can create a fifo
# start espeak in the background
espeak -f $ESPEAK_FIFO &
# or use tee to keep text on display too
cat $ESPEAK_FIFO | tee /dev/tty | espeak
# redirect stdout to fifo
this small script should be sourced in your terminal and afterwards everything displayed will be sent to espeak.