Yeah, it's far better than the initial one. There is no problem in the sentence structure.
As for few words;
メンバー seems like that you are only talking about a specific group of people. Just 人々 is the best.
話題 is not bad, but it's more likely "topic". I would use こと or 事柄.
単語 just refers to "words", so it's narrow in meaning. 表現 is better for "expression".
Incidentally, my attempt is;
私は、文化の異なる人々が同じ事柄について話すとき、使用する表現がどう違うのかに特に興味があります。