Hadith on Speaking: The Prophet speaks clearly for all to understand

Anas ibn Malik reported: When the Prophet, peace and blessings be upon him, would speak, he would repeat himself three times until he was understood. Whenever he came to people and greeted them with peace, he would greet them three times.

Source: Ṣaḥīḥ al-Bukhārī 95

Grade: Sahih (authentic) according to Al-Bukhari

عَنْ أَنَسٍ عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ كَانَ إِذَا تَكَلَّمَ بِكَلِمَةٍ أَعَادَهَا ثَلَاثًا حَتَّى تُفْهَمَ عَنْهُ وَإِذَا أَتَى عَلَى قَوْمٍ فَسَلَّمَ عَلَيْهِمْ سَلَّمَ عَلَيْهِمْ ثَلَاثًا

95 صحيح البخاري كتاب العلم باب من أعاد الحديث ثلاثا ليفهم عنه