Sprint has confirmed that it is, in fact, in talks with Japanese mobile carrier Softbank. The news leaked earlier today that Softbank may be making a $12.8 billion investment in Sprint, which "could involve a change of control of Sprint," according to the official statement. Here's the official word from Sprint: Sprint (NYSE: S) today confirmed that it is currently engaged in discussions with Softbank regarding a potential substantial investment by Softbank in Sprint. Although there can be no assurances that these discussions will result in any transaction or on what terms any transaction may occur, such a transaction could involve a change of control of Sprint. Sprint does not intend to comment further unless and until an agreement is reached. Reuters sources claim that Softbank is talking to various banks to finance a bid. Clearly, Sprint has declined to comment on any specific number, but if that $12.8 billion figure holds true, Softbank would be taking over two-thirds of the company. Developing…