Complex sentence: Due to the wide variation in volume, it is prudent to inquire before ordering one; a term sometimes heard in the Western United States, but not common elsewhere, is an Italiano for a short Americano, specifically a 1:1 espresso/water ratio.
Split into simpler sentences: Due to the wide variation in volume, it is prudent to inquire before ordering one. The term "Italiano" is sometimes used in the Western United States, but not common elsewhere, meaning a short Americano, specifically a 1:1 espresso/water ratio.