To answer this, you need to look at the words and try to think which of these words convey loneliness -- which of them would make you think that the people feeling these things are completely cut off from other people.
We can see this quality of farm life in how well the people had come to know the brook. To them, the sound of the brook had been a companion. It had become so familiar to them that it came to seem almost human.
Think about this -- what must your life be like if you think of a brook as your friend, if you think it's almost human. That would indicate to me that you are really cut off from other people and do not have any actual people to be your companions.