Hm... Interesting article. You should detalize a little your question, but anyway, I will try to answer. I am an English teacher (Russian native) living in Israel. And, you know, I will always recognize Russian Spy speaking English, for example. Not by means of pronunciation or grammar, but according to the way he thinks, speaks, forms his speach.
I wanted to keep it open-ended to see what everyone thought about the topic. Your comment is very interesting. Thanks!