Answered by Ustadh Tabraze Azam
It may take me up to 5 minutes to begin my prayer because of my fear to mispronounce the opening Takbir. What can I do?
Answer: Assalamu alaikum wa rahmatullahi wa barakatuh,
I pray that you are in the best of health and faith, insha’Allah.
Before you begin your prayer, say the ta`awwudh (I seek refuge in Allah from the accursed devil), make a short supplication to ask Allah to free you of misgivings, and then say “Allahu akbar” and begin the prayer.
See: A Reader on Waswasa (Baseless Misgivings)
And Allah alone gives success.
Checked & Approved by Shaykh Faraz Rabbani.