which one is better english with native speaker or english with teacher?

The answer is both of them and it depend on the function or which one do you want, grammar or speaking. If you want to speak English fluently, you may learn with native speaker because it help you in pronunciation. Well, you know speaking is easier than learning grammar, I don't know why but I thought speaking was easier than learning grammar. Because I can't role grammar until now, honestly. But sometimes, Not all non-native speakers have trouble communicating in English. Many speak at a native level, but many do not. The ability to communicate with people who speak a limited amount of English is actually a skill that can be developed over time with practice. Whether you deal with non-native English speakers often or rarely. It mean that we have to practice it, if we want to speak fluently and structural.