I don't have a hope of learning a second language so she's far ahead of me in that regard. CC, instead of thinking how her English may be 'bad' to you, how well do you know
your second language? Or do you not know one?
English is not an easy language to learn. There may be a few very specific rules - but a 1001 exceptions to every one. Japanese is also not an easy language to learn, so she's quite accomplished to know both, especially noting the significant difference in tense, pronouns, and sentence structure between the two.