1) “I have to go to a class to learn a language.”
Languages are mostly learned by practicing and using and so it is more effective to learn a language with individualized applications at one’s own pace.
2) “I have to learn a language through communication with people.”
This is too big an objective to start with. Somehow, non-native speakers would find it frustrating because few native speakers would be patient enough to communicate with them if their oral proficiency is minimum. Therefore, it’s better to start with more listening practice and gradually build up vocabulary and grammar, as well as confidence to speak in a second language.