Motion to dismiss under Speedy Trial Act requires the case be dismissed for failure to prosecute within 1 or 2 years.
The clock starts ticking on the day of arrest/citation, or indictment by grand jury, and stops on the day the trial begins.
WARNING: If a defendant fails to make a motion to dismiss "in a timely fashion", that right to speedy trial has been waived. So some poor suckers get convicted after waiting 15 years for trial, because their lawyer didn't make the motion until the day of trial.
Constitutional right to due process under 5th and 6th amendments also apply to speedy trial.
The Statute of Limitiations has no effect on the speedy trial requirement. Statute of limitations starts of teh day of the alleged offense, and ends on the day of arrest or indictment.
Some folks get a secret indictment that was never served for 10 years, so no due process. Those indictments get thrown out by the appellate courts.
Google Alabama Speedy Trial Act