In Back Talk (1999), Martin gives Frasier a newspaper from the day he was born. On seeing the newspaper headline, Daphne reads that Queen Elizabeth II (of the United Kingdom) has had another baby. This would put the date of the newspaper at the 15th of August 1950, the birth date of Princess Anne. However, in the episode "The Late Dr. Crane", the television announcement of Frasier's apparent death lists his birth year as 1952.
An emergency room patient claims to be Frasier Crane and then dies suddenly. His death would not have been reported before hospital officials checked his personal ID, which would have established he was someone other than Frasier Crane.
In the cafe, Frasier tells Roz all of the things he wants to do before he dies, including a translation of Freud. Frasier speaks French, but only a little German, and certainly not Austrian.