That night, lying in his bunk, Manjiro couldn't help trying the new words. "Buttons," he whispered. "Pockets. Shoes. Bread." Bread was hard to say. He tried again and again. "Captain," he said. "Whitfield."
"What are you doing?" Goemon said.
"Maybe if I learn some words, I can ask questions."
Goemon groaned. "More questions!"
"If we don't learn their language, how will we know what they intend to do to us?" (2.3.70-74)
Manjiro makes it seem like learning English is all about survival when he talks to Goemon, but he "couldn't help trying the new words." Hrm… doesn't sound like learning English is just for practicality—it sounds like Manjiro's actually intrigued by the language.