I work in Korea and I just had a co-worker correct me when I told one of our other co-workers "Good English!" after she said something in English. It's something that is said often in Korea in the English-teaching realm. At first, I agreed with him as it sounds a bit dumbed down. However, after thinking on it more, I really think there is no issue with telling someone "good English." It's an assumptive phrase like "(You used a) good English (phrase)." My co-worker said that one can only use proper English or speak English well. It seemed rather arrogant when he said it. Thoughts?