My Teacher won't let me swear on the internet

In class our teacher gave a little lecture about how he sees a lot of inappropriate language over our twitter accounts. As teenagers we tend to to use language that isn't nice. Our teacher has told us that if we want to continue to use profanity on our twitters we are to unfollow him and make a new twitter that is used to school purposes. I myself use foul language at certain times, but i do not want to have two twitters to use so I can force myself to watch how i type on twitter. Our teacher told us that if we decide to use bad language and he sees it there will be disciplinary actions forced upon us.
Yes it is true we have a free of speech but if the site is used for school use it is only right to follow the rules and to use the website with good use, not bad. Profanity has become apart of the teenage language, we've grown up with it and have learned the words easily from hearing them all the time. I don't have a problem with people who swear all the time on the internet because it is their choice of how they want to be seen by others.

As we grow up all we know about is the internet and social networking. Things such as facebook and what i brought up earlier, twitter. These social networking give us the freedom to say what we want, knowing that we have the ability to add anyone we want including family. That saying "Do you kiss your mother with that mouth?" Well it can go with this topic. If you speak like that on facebook or twitter do you speak like that to your parents or other family members? You also have to think about colleges and jobs, now-a-days they look you up on your social network sites to see what kind of person you are outside of school.
What I'm trying to get to is that if you feel like you shouldn't be saying something on the internet that could hurt you in the future, then don't say it at all.