The phrase "marching up cannon mouth" may seem confusing when it comes to spelling, but with IPA phonetic transcription, it becomes clear. The first word, "marching", is spelled as /ˈmɑː.tʃɪŋ/. The second word, "up", is spelled as /ʌp/. The third word, "cannon", is spelled as /ˈkæn.ən/. Finally, the word "mouth" is spelled as /maʊθ/. Reading the sentence with these spellings makes it easier to understand and pronounce.