4. The method of claim 2 , further comprising indicating an amount of non-native-like usage in the new natural language input.
2. The method of claim 1 , further comprising classifying one or more sentences in a new natural language input as either: non-native-like, if the characteristics of the new natural language input meet a selected threshold of similarity, using the refined classifier, to the indicators of non-native usage; or native-like, if the characteristics of the new natural language input do not meet the selected threshold of similarity, using the refined classifier, to the indicators of non-native usage.