March the cannon mouth is a phrase that involves two words frequently used in military jargon. The spelling of the word "march" is /mɑːtʃ/ and is pronounced as "marchh" with rounded lips. The second word "cannon" is spelled /ˈkænən/ and is pronounced as "kan-uhn" with the emphasis on the first syllable. Overall, the phrase "march the cannon mouth" has a very specific and tactical connotation, indicating the movement of heavy artillery during military operations.