It's important to note that "mea culpa" is a Latin phrase, and while it's commonly used in English, it's not grammatically considered an English word. Therefore, we pluralize it by adding "-s" as we would with an English noun.
It's important to note that "mea culpa" is a Latin phrase, and while it's commonly used in English, it's not grammatically considered an English word. Therefore, we pluralize it by adding "-s" as we would with an English noun.