mane mane jape, mukhe na kare akhyana
ei ihara manah-katha--kari anumana"
mane mane—within the mind; jape—chants; mukhe—in the mouth; na kare akhyana—does not express; ei—this; ihara—his; manah-katha—intention; kari anumana—I guess.
"This boy chants the mantra within his mind, but does not say it aloud. That is his intention, as far as I can guess."
Link to this page: https://prabhupadabooks.com/cc/antya/16/72