Answered by Ustadh Tabraze Azam
Question:  Is repeating phrases like Allah u Akbar allowed in the salah if they were not correctly pronounced once.. many times it happens that i am able to say “Allah u Ak” “bar” is not pronounced properly one time so i repeat it and say “Bar” again clearly. Does this invalidate Salah?  And sometimes Allah u Akbar overlaps when i go in sajdah and i finish it in sajdah and vice versa (i.e when getting up-finishing it in sitting position) does this affect the Salah in any way?
I pray that you are well, insha’Allah.
 No, you should not repeat the end of the phrase “Allahu Akbar” with the intention of correctly pronouncing it. This will open up the door to misgivings, and misgivings are from the devil. Don’t pay any attention to them. Say “Allahu Akbar” and continue. Don’t try to fix anything.
 Saying “Allahu Akbar”, such that it starts when you begin to move and ends when you reach the next position, is from the sunna as it ensures that no part of the prayer is silent or free of remembrance (dhikr).
[Shurunbulali, Maraqi al-Falah]
And Allah alone gives success.