How do I know if my civil rights have been violated due to a lack of speedy trial?

Good question. The issue is whether his right to a speedy trial has been violated. Your dad should consult his attorney about whether he wants to file a motion to dismiss for violation of his right to a speedy trial.  The seminal case on point is Barker v. Wingo. There are four main factors a judge looks at to determine if someone's right to a speedy trial has been violated. First is the amount of time that has passed. Typically 8 months is the minimum.  Second, has your dad requested a trial? Third, what is the cause of the delay? Is the State ready to proceed to trial? Has your dad wanted to go to trial? Fourth, what is the prejudice that your dad has suffered as a result of the very long delay? All four factors are important but no single factor is dispositive. Courts are hesitant to grant speedy trial motions, but if your dad has been prejudiced and the State has not been ready for trial, then it is definitely an avenue worth pursuing.