The spelling of the word "arreguin" can be a bit tricky to decipher. The correct pronunciation is [ah-reh-geen]. The "a" in the first syllable is pronounced like the "a" in "father," while the "e" in the second syllable is pronounced like the "e" in "pet." The "ui" in the final syllable is pronounced like the "i" in "machine." Therefore, the correct spelling of this word is "arreguin," with an "i" rather than a "u" in the second-to-last syllable.