It might be reasonable to suspect that you are seditious, but that suspicion would not be probable cause to arrest you (And it shouldn't be) because there is no evidence that a law has been broken.
this would be specifically protected as free speech. only libs would consider that sedition :-)
this AZ law reads the same way the Washington law used to read on cell phone use while driving. it was not a primary offense. you had to be pulled over for some other reason. might a cop look for a reason? sure. is that a bad thing? probably not. since our legal system seems to have no problem punishing cops for perceived excesses, it's probably not going to be a problem. most cops i know bend over backward to keep people from thinking there might be any excesses.
This is the crux of the matter. A secondary offense requires a more serious (primary) offense to occur before it can even begin to be enforced. This is what makes it both legal and non-profiling. Once a primary offense occurs then there is still the requirement for a reasonable suspicion that a person might be an illegal. A person unable to speak or understand English would provide that reasonable suspicion.
Please understand that probable cause and reasonable suspicion are the same thing in the eyes of the law, different words, same definition.
Please understand that the AZ illegal immigration act is legal, valid, and consititutional in the same way the a county or city enforces states laws, they adopt the statute in some manner (be it via citing code, statute, or by copying verbatim). It's sometimes called layed jurisdiction where, as long as the proper jurisdiction line of authority exists, the sub-governmental authority has valid and legal juridiction of enforcing the laws of the higher juridiction.
Here in the state of Washington, I could, as a municipal police officer, enforce state laws and regulations since the city is a sub-governmental unit of the state. Unless the state laws were cited by the city (in the case of misdemeanors or gross misdemeaners) the laws could not be tried in municipal court, but had to be tried in the local Superior Court of the state (County).
Lastly, By numerous Supreme Court or the United States rulings, a police officer is not obligated to respond to a call of distress, insure the safety of citizens, ir provide protection from criminal acts. They do not have to answer 911 calls if they don't want to. The main function is to investigate crimes committed in violation of state, county or municipal governmental laws, rules, or regulations.
The only constitutionally empowered authority to protect your life, limb, and property is YOU.