Is tệ a good translation for "bad"? I've never heard anyone say it before. Usually it's just "không tốt"
when talking about actions, "hay" (good) and "tệ/dở" (bad) are the adjectives used to qualify, not "tốt" and "xấu".
It seems the adverb "tệ" is more like "badly"?
it's an adjective
I agree. It's not bad. In fact, it's an easy phrase to translate.