What is the ruling on the adhan and imamate of a lisping person in a silent prayer?

According to the majority of scholars, the adhan (definition) of a person who stutters or lisps (al-althagh) is not sufficient (la yujzi'), and prayer behind him is not valid except for those who are similar to him, according to the majority of scholars. If the person who stutters or lisps replaces one letter with another, like al-mustaqin (one who says 'sa' instead of 'tha'), the prayer of those who follow him becomes invalid if he was able to learn and did not do so. However, if time is short for him, he should pray and then make up the prayer. Jurists have differed regarding the imamate of a person who stutters or lisps; some permit it with a degree of dislike (karahah), while others believe it is not valid. The preponderant and authoritative view is that the imamate of a person who stutters or lisps is not valid for others who do not have a lisp.