Ответ:

1. I don't think so. Everyone uses big words sometimes to emphasize their feelings about the object they're talking about. For example, a person can talk about something very interesting for him. He will accidentally put some big words when he is talking.

2. I don't agree with that. Teenagers have used to using simple words, but it doesn't mean they're always using simple words in conversations. Everyone is different, and teenagers aren't the exception. For example, they can talk about some scientific topics, then simple words aren't going to be the easiest way to describe something related to science.

Ну, если уж полностью не подойдет, то хотя бы идею можно взять из моих слов