Why is the word "se" necessary here?
Its is a reflexive verb:unir-se. so, eles SE unem.
Aquelo me muito ajuda!
If we wanted to say "The farmers and fishermen unite our family," we wouldn't need to use "se," right? Would it just be: "Fazendeiros e pescadores unem a nossa familia"?
Yes!! :) reflexive verbs are verbs which consequence is on ourselves. So, in your example that didnt happen, so you dont need "se"! (Congrats)
Eu entendo agora. Muito obrigado!
How about "Farmers and fishermen unite themselves." Not the best English, but other times, "se" adds the concept of "self."