Loudly saying, 'Yaa Allaah!" in Salaah

Q: Salaah-416: A man is in the habit of loudly saying, "Yaa Allaah in salaah. What is the ruling?

Answer: This habit is Makrooh and needs to be forsaken. And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.2