The phrase "marching up the cannon mouth" is spelled phonetically as /ˈmɑːrtʃɪŋ ʌp ðə ˈkænən maʊθ/. The first word, "marching," is pronounced with a long "a" sound, followed by a soft "ch" sound, and ending with an "ing" sound. "Up" is pronounced as expected, with a short "u" sound and a hard "p" sound. "The" is pronounced with a soft "th" sound, and "cannon" with a soft "c" sound and a hard "n" sound. Finally, "mouth" is pronounced with a long "ou" sound and a soft "th" ending.