Let's discuss Britney's voice. Her first 4 albums

[Guest]

Her voice from baby one more time to in the zone suffered a lot of changes and her voice note isnt the same on any of her first 4 albums

On Baby one more time we have her real register, which is low and deep with hight notes, she was 16/17 but sounded like a WOMAN in her mid 20s. She had a VOICE

On oops i did it again she starts using her nasal voice and reaching a higher pitch, see, the change of notes between BOMT and OIDIA it's very noticeable

 

But the even more noticeable change comes with Britney 2001, the nasal voice is on its full force and it's consolidated, her voice it's so pitched and it's when the "Britney voice" starts being referenced as such.

On in the zone She lowered down a lot compared to Britney and OIDIA,she doesnt sound like a teenager anymore, she sounds like a woman, but sounds different from BOMT, this is the voice she used for a while and honestly her best voice style IMO.