The word "hyperthyrion" refers to an overactive thyroid gland, and its spelling can be explained through IPA phonetic transcription. The word is pronounced as "hahy-per-thahy-ree-uhn," with the stress on the second syllable. The "y" in the first and third syllable represents the sound of the short "i" vowel, while the "th" sound is formed by placing the tip of the tongue between the teeth and blowing air out. The final syllable ends in the sound of "yun," which is a combination of the voiced "y" sound and the "n" sound.