While reciting Namaz,many times my tounge makes mistakes in reciting unintentionally. Example- If have to recite 'Arrahmaanirraheem' , then sometimes the sound of 'r' does not come out or sometimes such other mistakes also happen. Also, Sometimes I feel a doubt whether I recited the verse or part of namaz correctly or it went wrong. What should I do? Till now I have been breaking my namaaz and then restarting again from beginning and reciting correctly and completing the prayers. What am I supposed to do and how to correct it?