Disclaimer
I am a casual using hacks and amateur knowledge to translate.
There's at least one line here I'm not 100% sure on. If it sounds weird / doesn't flow, that's on me. Sorry!
Please refer to Hetascanlation's work (when they get there) as the definitive translation.
Translation Notes
General:
Fonts are swapped around based on their tone/volume, so it might look random, but I'm just trying to replicate the original font choices.
Page 4:
• "Picking flowers" and "pheasant hunting" as a euphemism for using the toilet appears to be shared between Japan, Vietnam, and Thailand, and perhaps other Asian countries. I can't find its origin (though the theory many have is that the postures one assumes when urinating/defecating is similar to the posture of flower picking or pheasant hunting), and the oldest Japanese source I could find was 1986 - but it likely dates back far before that.
• While the phrase "see a man about a dog" did originate in Britain (in an 1866 stageplay), its usage to euphemistically refer to going to use the toilet appears to be more common in the US. The original non-facetious meaning was probably to place or settle a bet on a race (as an alternative version of the phrase is "see a man about a horse"), but the idiom is generally used nowadays as a polite way of saying one is going out, but do not ask where - perhaps with the implication that one was about to be, or has been, up to no good.
Page 6:
• "'O sole mio" is a famous Neapolitan song written in 1898, and its title translates to "My Sun[shine]."
• Neapolitan itself is a Romance language of the Italo-Romance group spoken in Naples and most of continental southern Italy. It is named after the Kingdom of Naples, which once covered most of the area. Italian and Neapolitan are of variable mutual comprehensibility, though with notable grammatical differences (Neapolitan has nouns in the neuter form and a unique plural formation, etc).
• As Italy represents the north, he would naturally fall back on standard Italian in private, instead of Romano's Neapolitan.