How to split a list by comma not space
Using a subshell substitution to parse the words undoes all the work you are doing to put spaces together.
Try instead:
cat CSV_file | sed -n 1'p' | tr ',' '\n' | while read word; do echo $worddone
That also increases parallelism. Using a subshell as in your question forces the entire subshell process to finish before you can start iterating over the answers. Piping to a subshell (as in my answer) lets them work in parallel. This matters only if you have many lines in the file, of course.
I think the canonical method is:
while IFS=, read field1 field2 field3 field4 field5 field6; do do stuffdone < CSV.file
If you don't know or don't care about how many fields there are:
IFS=,while read line; do # split into an array field=( $line ) for word in "${field[@]}"; do echo "$word"; done # or use the positional parameters set -- $line for word in "$@"; do echo "$word"; donedone < CSV.file