Depends whether you want a clout round the ear.
chatterbox
Such a person is called a chatterbox.
loquacious
Tu hermana menor habla mucho en el teléfono.
A proper term would be "loquacious" (talkative, garrulous, verbose). Slang terms include "chatter box," babbler, or "motormouth."
what do you call a person who talks very less
Princeton, But When He Talks On Interviews He Can Get Romantic
Professional Poker player. I think he won 2 bracelets in the World series of poker. He talks a lot and wears sunglasses. His sister is also a Professional poker player.
you call her your daughter's husband's sister
You don't call your brother's sister your aunt. Your brother's sister is your sister, or you. Your aunt is the sister of your mother or father.
There are a lot of people who talk before the missions of Call of Duty: Modern Warfare 2. In the way, way beginning, there is a man who is talking. He is General Shepherd. Captain Price also talks once you beat the mission, "The Gulag." Captain MacTaverish, or Soap, talks before some missions. Ghost is just a side character who sometimes talks.
You would call your sister's daughter your niece.