Mac sing a song "In the Hall of the Mountain King" using word you gave.

CellosSing

#!/bin/sh
################################
# set base word
################################
DEFAULT_WORD="foo"
word=$DEFAULT_WORD
# if argument exists, update word with argument[1]
if [ $# -gt 0 ]; then
word=$1
fi

################################
# start generationg song sentence
################################
sentence=""
# magic number of word count to sing a nice song
REPEAT=26
for i in `seq 1 $REPEAT`
do 
sentence="${sentence} ${word}"
done

# print sencence for debug
#echo $sentence

################################
# run say command
################################
# save
#say -v Cellos -o ${word}.aiff $sentence
#echo audio file saved.

# sing
say -v Cellos $sentence