I am not a native English speaker and I tend to construct sentences like "It is an interesting question, that.". My girlfriend who is a native English speaker always tells me that I am talking like yoda everytime I construct such kind of sentences. So I wonder if grammatically speaking sentences of the type just mentioned are correct or not. I guess it could also be that it is just a matter of style. I think I have seen this pattern of sentences in some academic books, specially from the 90's. So my doubt is essentially whether the two following sentences are both grammatically correct.
(1) That is an interesting question.
(2) It is an interesting question, that.
Based on some comments, I think it might be helpful to know that I am a Spanish native speaker, and in Spanish such pattern of sentences are common too. So I guess my Spanish could be interferring with my English usage.