Apophlegmatism is a rare and complex medical term that refers to the accumulation of mucus in the airways, leading to difficulty in breathing. The word is pronounced as /æpəflɛɡmətɪzəm/. The first syllable is pronounced as "a-puh" and the second syllable is stressed, pronounced as "flĕg." The third and fourth syllables are pronounced as "muh" and "tiz-uhm" respectively. Such complex medical terms often require knowledge of phonetics and morphology, as well as their associated meanings, to understand their spellings and pronunciations correctly.