Just one reason? one big reason is they needed jobs. Most immigrants planned to become rich and then go back to their own country. Others immigrated because America was rumored to be perfect.
I do not think so because there are many American-Indian tribes and cultures, but not all of them speak the same language.
For example, Navajo and Cherokee will not speak the same language, because they are from different areas.
Hope this helps you!
Answer:
1. NATIONAL GRANGE MOVEMENT (1868)
2. INTERSTATE COMMERCE ACT (1886)
3. FARMERS' ALLIANCES
4. OCALA PLATFORM