"Sık sık bahçeye gider."
Translation:He often goes to the yard.
No. Duplications are used to make support the meaning in many words, to make this given word understood better. There is no English equivalent for that.
"-ça" suffix indicates the way it is done, same as the -ly suffix in English.
Let's try it with another word;
Hızlı = fast
Hızlıca = fastly
Hızlı hızlı = fast (the word "fast" is the focus point in the sentence)