The Arabic letter "خ" (khā) is pronounced as /x/ in English. It represents the voiceless velar fricative, which means it's a sound made by constricting air flow through the vocal cords while bringing the back of the tongue against the soft palate and the back of the throat. In contrast, the Persian letter "م" (meem) is pronounced as /m/ in English. It represents the bilabial nasal sound, which means it's a sound made by blowing air through both nostrils while bringing the lips together.