In regards to the recitation of Al-Fatihah by the one leading, if the Imam who is leading the congregational prayer, pronounces the letters in Fatihah, for example making “Z” sound instead of “DH” (Ihdinas-siraatal-a-zeena instead of idhninaa-siraatal-adheena) does this mispronounciation nullify the prayer?
Mistakes are of two types لحن جلي and لحن خفي. The clear and obvious mistakes are labeled as: لحن جلي, This type of mistake should be corrected and avoided because it may lead to a change in the meaning, grammar, or incorrect in the Arabic language. The person that makes this mistake may be a sinner if there is no valid excuse. لحن خفي are the hidden mistakes that one should also make an effort to fix.