未呀 (Cantonese) etymologically related to 吗 (Mandarin)?
In Cantonese, you can say 你食咗飯未呀？ and in Mandarin you can say 你吃了饭吗？

未呀 is mei6 aa3 and 吗 is ma. Is there any chance that 吗 has etymological origins as a contraction of 未呀 or is the similarity of the pronunciations simply coincidental?

Question

未呀 (Cantonese) etymologically related to 吗 (Mandarin)?
In Cantonese, you can say 你食咗飯未呀？ and in Mandarin you can say 你吃了饭吗？

未呀 is mei6 aa3 and 吗 is ma. Is there any chance that 吗 has etymological origins as a contraction of 未呀 or is the similarity of the pronunciations simply coincidental?

Answer

no, they are two different words

Answer

There is such relation between 没 and 未.But what you’ve said above maybe just coincidence.

Answer

The word "呀" in "未呀"actually can be omitted. 
Moreover, the meaning of "未" is "didn't ", "呀" and "吗" are mood auxiliary words. the mood meaning of "呀" has many meanings, and "吗" usually just expresses doubt/question. 
Therefore, in this sentence, the similarity of pronunciation is just a coincidence.

Answer

they are similar,,,and 未呀 means 没呀