Sometimes grammar can give away a non-native speaker, particularly: “Show me how it looks like.” The use of how here is hard to explain, but it’s wrong. It should be “what it looks like”. This is an instant giveaway usually.

But even native English speakers have weird ways of saying things. One grammatical error I hear a lot in people from the Appalachia region is the “needs done” construction. Always sounds bizarre. ie. “This work needs done by tomorrow.” Also the positive “anymore” construction. ie. “You see that a lot anymore” (“these days”).