They can talk with the "English" (non-Amish) all they want.
Yes, non-Amish can go to Amish church. They will probably ignore you though.
There are no rules. I've been to amish country many times and talked with many amish people. Some even work in convienent stores at the cash register
Some Amish people are called "Mennonites".
Amish people are people who only have Amish friends , really religious, they stay in an Amish community, and have no electric or electronics.
They are shunned.
Most Amish don't use technology. They see it as a distraction, and they have other religious views about it. Each Amish community has a sort of "rulebook" called an Ordnung that is different for each community- for example, one community might be allowed to have a telephone for the entire community, and for another it wouldn't be so. Also, a lot (NOT ALL) Amish people don't feel comfortable with associating themselves with non-Amish peoples and/or don't feel a need to explain themselves. Some people were Amish when they were younger, though, and have "converted" to a non-Amish lifestyle, so don't be surprised to see answers from once-Amish people.
Amish are called Amish because the founder of it was Jacob Ammann
The same as white Amish people.