Is the prayer valid if the worshiper says "By God [wa-llāh], Allahu Akbar" instead of "Allahu Akbar" in the opening takbir due to difficulty in pronunciation?

The opening Takbir (Takbirat al-Ihram) is one of the pillars of prayer; prayer is not valid without it. It must be uttered correctly, free from grammatical errors (lahn) or alterations.

If the questioner is unable to pronounce the opening Takbir without adding the letter "waw," then her prayer is valid, according to the Prophet's saying, "When I command you to do something, do as much of it as you can."

However, if she is able to pronounce it without adding a "waw," then adding it invalidates the prayer according to some scholars. Other scholars say that a grammatical error in the opening Takbir does not matter.