السلام عليكم ورحمة الله وبركاته احسن الله إليكم 1. Is it permissible for an imam to lower his voice tone during takbir when rising to sit for tashahhud? ​2. Can an imam briefly say a word aloud in the final rak'ah to alert followers before making sujud as-sahw (e.g. after salam)?

Ustadh AbdulAziz al-Haqqan

No, he says the takbir as he usually does. After the salam he just says Allahu Akbar and they go into the prostration, and as for saying a word, I know of no evidence for that, and Allah knows best.