I am disappointed that Disney chose this name for their "The Princess and the Frog" character. Why? Because it's not Creole, French, or African (thus having little to do with the Disney princess's heritage). It likely comes from Tatiana, a Russian name from a Latin family name with no known meaning, as a short form. And the chances of it being used in 1920's New Orleans are slim to none, especially compared to popular names of the day like Fannie and Ruth. Disney was supposed to have named her Maddy (which would have been more accurate if it was a nickname for Madeleine), but it's similarity to a derogatory term, "mammy," made it less desirable, and I guess the public wanted something more in-step with our modern created nature, not caring about accuracy, so Disney found this gem that is one letter different from "tiara." Coincidence? And while Tiana's similarity to "tiara" is creative, it would not have been hard to find a different French-Creole name for the character, something the people of New Orleans in 1920 (or 1900-ish when she was born) would use.
Why else am I disappointed? It sets the bar low. Copy-cat parents and fans will use this name without looking into its origins. They will never ponder the meaning of Tiana (past "Disney princess") and will never consider the history of French-Creole or African-American names. They will just use it, and that will be that. And people should research names before choosing one. To be clear, Tiana, like Tatiana, has no meaning. If you want one, it means "from the house of Tatius." There is a chance it could be related to Titania, who was the queen of the faeries in literature, but Titania means "titan." Unfortunately, many sites list Tiana as a Slavic name meaning "fairy queen," which is not the case, and probably comes from Titania as a mis-translation. Others suggest it means "princess" from the Greek name Tia, but there isn't even enough evidence to say Tia means princess, much less Tiana. Even if it were true, I'd still be unhappy about this name for Disney's princess.
A lot of the positive response for "The Princess and the Frog" was because it was Disney's first African-American (Creole?) princess. They had a lot of responsibility to make her credible. The name Tiana ranked since 1975 and is now at #387, but had been used since at least 1950. Even though the name has been popular since 1975, it was not a good choice for a girl from New Orleans in 1920. Something recently popular is not authentic for this character. Acadia, Alexandrine, Fleur, Delphine or Sidonie - authentic.
All the other princesses have some kind of meaning or authenticity to their name. Think about how Snow White, Cinderella and and Jasmine had names that lent credibility to their overall character. Tiana does not enhance the character of this movie the same way, and only enhances the "shine" of being a princess created this decade.
P.S. For those of you named Tiana, I am not criticizing your name, I am criticizing Disney for using it as a character name.