Actually, it's silent. Some people instead aspirate the J or pronounce it like an English H.
I think it's the pronunciation of the "j" that is under discussion. From anything I've ever heard or been exposed to, Spanish "j" is pronounced more or less like English "h."
Mija is slang, it's a contraction. It's actually "Mi hija", but when contracted its like the work "can't" (which is "can not").
Oh, it is Spanish, just very colloquial Spanish. Much like "aint" is very colloquial English.
Sounded like Mi ihah for some reason. I think the audio said it too fast
"H" is not pronounced in Spanish and "j" sounds like English "h." "Mi ihah" is pretty much what this phrase should sound like.