Если вы хотите прочитать входные данные два по два и сохранить их в массиве, как насчет:
message="It's wings are too small to get its fat little body off the ground"
while read -r w1 w2 message <<< "$message"; do
arr+=("$w1 $w2")
[[ -z $message ]] && break
done
for (( i=0; i<${#arr[@]}; i++ )); do
printf "arr[%d] = \"%s\"\n" "$i" "${arr[i]}"
done
Вывод:
arr[0] = "It's wings"
arr[1] = "are too"
arr[2] = "small to"
arr[3] = "get its"
arr[4] = "fat little"
arr[5] = "body off"
arr[6] = "the ground"