Will I be sinful if my daughter picks up my lisp in some letters while I am reviewing the Quran with her, and will I receive the reward for teaching the Quran ( اجر تعليم القرآن الجاري) if I help her memorize it?

It is permissible to recite the Qur'an if the letters are not altered, but it is not permissible to teach others, especially children, if that leads to incorrect pronunciation that is difficult to correct. Memorizing the Qur'an should be avoided if it leads to a defect in the students' learning. One can participate in helping the teacher by encouraging the child to revise, by motivating her, and by letting her listen to the verses recited by proficient reciters. The questioner will be rewarded for all her efforts in assisting in this matter, and she will be rewarded for teaching her daughter, as following up on her memorization is an ongoing charity. She will also be rewarded for her good intention if an excuse prevents her from doing so.