What is imaalah?

Question
What is imaalah?
Anwer
Answer is a mixing of the ya' and alif so that the sound is approximately 50% alif and 50% ya', and a mixing of the fathah so it is approximately 50% fathah and 50% kasrah'. 
The only word in the Qur'an in which Hafs 'an 'Aasim  has imaalah is the word: in aayah 41 of surah Hud. 
To listen to it read and its explanation (in Arabic) please see:
https://www.youtube.com/watch?v=RIWLChkmjoI