Tham a Rai? ทำอะไร​อยู่​

On Sunday, I met a new Korean foreign student that my family is hosting to practice English, and I was surprised that my family told her that I am learning Thai. I am, but the process is very slow like many other things in my life. She asked me to share what I have learned. I realized that reviewing my blog would be good as I shared.
My brother said that he recalls that mom says nontombelliyuu a lot, saying that it means What are you doing? I have been looking around for a clarification, and I found that it is spelt​?​๋​ ทำอะไร​ nontombelliyuu seems to have a lot of extra stuff. It is actually pronounced "tham a rai." www.thai-dictionary.com/id/218172 has a good explanation. ทำอะไรอยู่​ is tham a rai yuu. Yuu seems to adds a present moment aspect to the question. What are you doing now?