No, there’s no legal requirements to say the pledge or anything. I’ve never seen it done outside of schools, it’s just a weird tradition that has been carried on.

In my high school nobody in my classes actually said it, but one of the teachers or the student council president would say it over the intercom (we didn’t even stand for it, usually just went back to our work while they talked).

As a younger child in elementary school I remember we were expected to say it, and I do remember a couple kids getting yelled at for not saying it (by the teacher, I don’t think there was any formal punishment). I know some Muslim children would say the whole thing and leave out the “under God” part.

I never paid much attention to it until I got older and realized how weird it was. I’m hoping it goes away eventually.

1. The Pledge of Allegiance was first created in 1892 to foster a sense of national unity. It was brainwashy even back then, especially having children recite it every morning, but it wasn't really intentionally malicious. It was intended to instill a sense of national fraternity in a fractured group of people, during a time that political tensions ran high and America was being filled with a large percentage of immigrants. Giving everyone an identity as Americans was important in moving the country forward at the time. That doesn't make it not nationalism, but at the time it was instituted I can understand where they were coming from.

Adding the "Under God" part and requiring it to be recited every morning before class wasn't instituted until 1954 during the Cold War era, when adults were worried that their children were commie spies. Their way of solving this was to shove Christianity and American Nationalism down the throats of everyone within earshot.

2,3,4. Via the Pledge's Wikipedia page:

In 1940, the Supreme Court, in Minersville School District v. Gobitis, ruled that students in public schools, including the respondents in that case—Jehovah's Witnesses who considered the flag salute to be idolatry—could be compelled to swear the Pledge. In 1943, in West Virginia State Board of Education v. Barnette, the Supreme Court reversed its decision. Justice Robert H. Jackson, writing for the 6 to 3 majority, went beyond simply ruling in the precise matter presented by the case to say that public school students are not required to say the Pledge on narrow grounds, and asserted that such ideological dogmata are antithetical to the principles of the country, concluding with:

If there is any fixed star in our constitutional constellation, it is that no official, high or petty, can prescribe what shall be orthodox in politics, nationalism, religion, or other matters of opinion or force citizens to confess by word or act their faith therein. If there are any circumstances which permit an exception, they do not now occur to us.

So as of current day, no, you cannot be compelled to stand and recite the Pledge. You WILL most likely receive nasty comments from your homeroom teacher, particularly if they are religious and/or older folks, and can be sent out of class to the principals office for basically any reason or no reason including this. It's against the law for the principal to leverage punishment against you for not reciting the pledge, but they can and will make your life very difficult if they feel like it without direct "punishment".

But in general, no, there is no legal punishment or precedent for someone who does not recite the pledge of allegiance. At worst, if you're accused of being a spy or of treason, it will be wielded as evidence that you are "un-American" and act as "proof" that you hate America. But it is not a punishable offense by itself.

1. As school children, we swore this oath. It describes loyalty to the flag and (more importantly) the nation and ideals that the flag represents.
2. As a child, I would just be silent during the 'under god' part. No one noticed. If they had, there isn't really anything they could do about it.
3. There have been lawsuits. Basically, you are not legally obligated to say it. There would be a lot of peer pressure to do so, because each of our school days would start with the whole class saying it.
4. Again, it is controversial, but you are not technically forced to say it.

Here is a breakdown of what the pledge means:
"I pledge allegiance to the Flag of the United States of America"
I swear loyalty to the flag
"and to the Republic for which it stands,"
and to the government it represents
"one Nation under God,"
a country guided by the Lord!
"indivisible, with liberty and justice for all"
united, with freedom and justice for everyone*

*terms and conditions apply

The long and short of it is that the pledge of allegiance is exactly what it says on the tin; you are pledging that your loyalty is to the flag (by proxy, to the United States). However, as a US citizen, one has a 1st amendment right that is supposed to protect you from being forced by the government to say the pledge (otherwise known as compelled speech). Constitutionally, you cannot be arrested or otherwise punished for not saying the pledge, or for expressing distaste for the pledge, leaving out the "under God" part while reciting the pledge, or even saying that you think the flag is nothing more than a nationalist propaganda symbol.

That all said, I feel like there is at least one or two stories a year where a student is accosted by a teacher because they refused to recite the pledge. Any teacher who does this is setting themselves and the school up for a lawsuit, as accosting/punishing a student for not reciting the pledge is flat out unconstitutional..

On a different note, as an American who grew up mindlessly citing the pledge throughout my K-12 years, it was a pretty harsh realization when I learned that this is essentially a kind of indoctrination. I honestly feel a bit gross when I go to my kid's school events and the first thing they do is trot out the flag and start the pledge. I wouldn't be surprised if there was a push to have it removed as a regular thing at public schools in the US (nor would I be surprised at a reactionary response from the "patriots" in our country if there was a movement against the pledge...).