会 instead of 能 is better. Both should be accepted.
They are both okay.
Often people say, “我会说” to mean "I can speak," i.e., "I know how to speak." “我会说流利的西班牙语。” You can also say, “我西班牙语能说得流利,” meaning "I can speak Spanish fluently."
This sentence refers to the degree of attainment. 能 is better.
Is this OK? 我会说西班牙语说得很流利
This is the response I would have given
我会说流利的西班牙语 should also be accepted.
But woukdnt 流利得说 be better?
当然啊,因为那门语言是我的母语哦 xD