He doesn’t stop to muse about it; it’s a short, descriptive essay. I recall my aged tea ceremony teacher did use [jo:] to refer to herself when speaking Portuguese; it’s quite distinct from pt. [ew], so it stood out. I wonder if it’s just a phonetic shift, or a Spanish loan out of place, or if it’s derived from some regional Brazilian dialect I don’t know. At any rate I’d think the Japanese would be the most prone to adopt new pronouns easily; hell, I’m still unconvinced “personal pronouns” is the best way of thinking about them in jp…