- Japan was given to the Portuguese by the Chinese, who called it Riben in Mandarin. Nippon is a near enough translation of this term for the Portuguese language to operate.
- Wayfarers' Chinese language, one which the first Portuguese to land in Japan might have spoken, was either Shanghainese or Hokkien (the dialect from Fujian). Nippon would have been termed Zeppen by Shanghainese. Nippon would have been called Jitpn in Hokkien. Nifon would be connected to both of them.
- The Japanese spoken by the Jesuits who wrote the lexicon would have been affected by the Japanese spoken in Nagasaki, which was the Portuguese primary base at the time. Nagasaki's accent is known as the Nikei-accent system, and it is extensively used across southwest Kyushu. Regardless of the number of moras in the word, it has two distinct tonal patterns. As a result, Nippon is Ni-Pon, which translates to Ia-pam.
The word Iapam was later coined by the Italians. Padua was the largest Italian city at the time. Given the circuitous route by which the term Iapam arrived in Padua, it was mistranslated as Giapan based on the Italian used at the time. The name Giapan was introduced in an English trip book called 'The History of trauayle in the VVest and East Indies...' published in 1577. Since the Italian Gi resembles the English J, it was no surprise that the English transformed Gi to J, finishing in Japan. As a result, the path by which Nippon became Japan is convoluted, beginning with Portuguese being impacted by the sort of Japanese spoken by the Jesuits in the sixteenth century. Then, out of the three names employed by the Portuguese, Iapam was noticed and received in Padua, and it was then translated into Italian as Giapan. Then there's the story of how Giapan, which was initially used in an English travel magazine, was anglicized into Japanese.