Two common words that are mispronounced in Arabic are
خزانة و صحاح
خزانة = treasurey, safe deposit
صحاح = correctness
خِزانة – this word actually takes a kasrah on the first letter
صَحاح – this takes a fatha on the first letter
Often times students will switch the kasrah and fatha, and because it is used so often people think it often correct when in reality it is incorrect. A phrase that will help with this confusion is:
لا تَفْتَحِ الخِزانةَ ولا تَكْسِرِ الصَّحاح.
What is really amazing is that this phrase has 2 meanings:
1.) Don’t open the safe box and don’t break what is correct
2.) Don’t put a fatha on the word خزانة, and don’t put a kasrah on the word الصحاح.
We hope this helps!!