While watching Sword Art Online, in the third episode when Kirito receives a pre-recorded message from Sachi on Christmas she says that she'll sing but instead hums "Rudolf the Red-Nose Reindeer".
This came from the dubbed version of Sword Art Online, it also made me remember that some other anime i've seen dubbed, when a character says they'll sing, alot of the time they hum instead.
I am wondering, when an anime is dubbed are songs changed to be hummed or even changed entirely due to language difference or is it a translation error when say "sing"?
Note: i am not referring to Insert Songs