those words are your Shibboleths, words that give your origin away.
When I was in Germany, friendly people used to compliment me on my language skill saying "your German is good!". To which I would reciprocate: "thanks, yours too!"
My ex-wife whose native language is Spanish worked hard to eliminate her accent because she got tired of people calling her accent “cute.” Her shibboleths were anything with a schwa. The whole concept of schwas offends her sense of vocalic purity.
When I was in Germany, friendly people used to compliment me on my language skill saying "your German is good!". To which I would reciprocate: "thanks, yours too!"