What is the ruling on extending vowels (madd) during the Takbir?

Primary text

Extending the vowel sound improperly during the Takbir is forbidden if it causes a change in meaning. For instance, extending the first hamza of Allah to make it sound like a question, such as saying 'Aallahu,' invalidates the Takbir. Similarly, extending 'Akbar' by adding an extra alif changes the word to the plural form of 'kibr' (drum), which is impermissible because the meaning is altered.