If you read the other comments on this page you'll see the words we have for this sentence.
Please read these tips:
TIPS TO HELP YOU LEARN + HOW TO REPORT A PROBLEM
And check out the Greek Forum here with more links. https://forum.duolingo.com/topic/936
Duolingo teaches US English.
These are the words we have for "μαμά" out of respect for all versions of English. So, don't use expressions such as "rubbish" but try to learn a little about the world.
So, please show a little respect for "mom" which is used by millions of people. I told you that months ago.