As Muslims we believe that this life is nothing but a test. We believe that this life is nothing and that the next life is our real destination. In Islam Allah says in the Quran: Allah does not burden a soul beyond that it can bear[2:286] From this verse we can infer that Allah knows that whatever we are struggling with we can get through it. Allah says that he won’t give someone a problem if he knows u can’t get through it. Allah says in the Quran: We will certainly test you with a touch of fear and famine and loss of property, life, and crops. Give good news to those who patiently endure[2:155] Allah is saying in the Quran that Allah will test every single one of us through any means. And he also says give good news to those who patiently endure. Allah says in the Quran: So, surely with hardship comes ease[94:5] Allah is saying that no matter what u are going through eventually after that hardship will come ease Abu Huraira reported: The Prophet Muhammad(ﷺ) said, "No fatigue, nor disease, nor sorrow, nor sadness, nor hurt, nor distress befalls a Muslim, even if it were the prick he receives from a thorn, but that Allah expiates some of his sins for that." [Sahih Bukhari 5641] From this we can see that the prophet Muhammad said that any sort of pain that anyone goes through even as small as a prick of a thorn some of your sins are wiped away Narrated by Aisha: The Prophet (ﷺ) said, "Such a person as recites the Qur'an and masters it by heart, will be with the noble righteous scribes (in Heaven). And such a person exerts himself to learn the Qur'an by heart, and recites it with great difficulty, will have a double reward."[Sahih Bukhari 4937] This means that those who struggle to read the Quran who may be stuttering or who may stumble over their words will be getting double the reward of what the person who prays beautifully. The person who prays beautifully gets 10 good deeds for every letter he recites so if u have difficulty then you will get double that. “Sometimes when Allah wants a certain level of jannah (heaven) for someone and their deeds can’t get them there alone he gives them hardship”-Anonymous From This we can see that if Allah loves his servant then he tests them and in this case it may be stuttering so he tests you with this speech impediment and elevates ur status. So now back to your question “what’s your reasoning for god giving us such an ailment?” This may just be a way of god testing us and he wants to see if we turn back to him. You might be thinking but I’m not a Muslim so why do I still have problems. That’s Allah testing u to see if u will change ur way and come to the correct path or whether you want to go astray When disbelievers go through trials they reach a crossroads where they will be confronted with the realities of life and the greater implication which can be in the form of a "mid life crisis". At this crossroad some find God and accept the truth. Others go deeper into their despair and turn to their desires to cope.