The Cameroon international moved to Barcelona from the Gunners in 2012, but has struggled to command a first-team spot with the Catalan outfit.
He told AS: "In comparison to my first year, I feel much better. When you move to a new country and have to adapt to a new language, a new culture, it requires time.
"What I have discovered here is that we are like a big family and everyone has welcomed me with open arms. Cesc (Fabregas) is like a brother to me. He took me by the hand and guided me through those difficult early moments, and that made me feel better right away.
"Now I understand the language a little more, although I still struggle to express myself. Life's much better and I am very happy to be here."
Song spent seven years with Arsenal.