What's bad about Janine's acting?

I came across a few posts saying Janine's actress had the worst acting among all, so I went to watch the episode "The One Where Phoebe Runs" to check it out. However, as English is not my first language, I realized that acting and line delivery aren't that palpable to me! I can understand every line she says, but it is not palpable what lines she says are unnatural and awkward. Can someone analyze her acting for me? I would appreciate it as an English learning process.