1) Yes, a manager can tell you what to say or not to say to a fellow employee. Employers can set the terms and conditions of employment, and if somone doesn't want to abide by those terms and conditions, he or she should seek other employment. The only things an employer can't do is require things illegal in and of themselves (no requiring employees to participate in tax fraud); however, unless you work for a government agency, there is no law saying that an employer can't tell you what you can say (with one narrow exception, discussed below): the 1st Amendment, which guarantees freedom of speech, applies vs. the government, not private companies.That narrow exception: under the labor laws, there are limitations on the employer's ability to prevent you from discussin things related to unions, organizing, etc.2) If you violate what your employer tells you to do, you can fired for it, and there is no wrongful termination in that case, unless the employer eithera) violated the terms of an employment contract or union agreement in the termination;b) discriminated in the termination on the basis of race, sex, religion, age over 40, disability, etc.