How can the problem of stuttering and difficulty in pronouncing some verses of the Qur'an be treated, and is it permissible to lead congregational prayers with this difficulty?

Stuttering does not prevent one from reciting the Qur'an with tajwid and tartil. Tartil is the Sunnah of recitation, and it means reading slowly and deliberately, pondering over the meanings. To address speech difficulties, it is recommended to practice and be deliberate in recitation outside of prayer, and to try reading words and verses letter by letter. If a Muslim exerts effort but is unable to improve their pronunciation, there is no blame upon them. However, it is advised not to lead people in prayer unless one is confident in their ability to recite without errors or stuttering, in order to preserve the dignity of the imamate and to relieve oneself of any embarrassment. One should not grieve over congenital stuttering, as there were great scholars among the predecessors who suffered from it, and that did not diminish their status.