The trial of Fazil Say, who has played with the New York Philharmonic, Berlin Symphony Orchestra and others, starts today. His tweets included one that joked about a call to prayer that lasted only 22 seconds.
Mr Say tweeted: "Why such haste? Have you got a mistress waiting or a raki [a Turkish alcoholic drink] on the table?"
Islam forbids alcohol and many Islamist consider the remarks unacceptable.
Prosecutors have charged him with inciting religious hatred and insulting Islamic values. He faces a maximum 18 months prison term, although any sentence is likely to be suspended.
Mr Say, a critic of Turkey's government, has denied insulting Islam.