Now, screenshots posted on Twitter by @Salczak reveal “Polish Cortana” in action and it seems in Beta rather than Alpha. The tweet also claims Windows Phone 8.1 GDR2 coming on 8th of October for dev preview devices.
Polish Windows Phone users! Get ready for Polish Cortana! Windows Phone 8.1 Update 2/GDR2 (PfD) is coming- 08.10.2014 pic.twitter.com/AcJRODPbxZ
— Sylwester Sałek (@Salczak) September 14, 2014
@Salczak is known to be a dependable source in past, so it may be true. Though, dates are subject to change, still early October seems more or less confirmed now.