She expressed frustration at how her fluency would fluctuate: her ability was highest when she was passionate about the topic in question. She was perplexed about the mysterious factors that enable good writing. I sympathised.
This conversation affirmed in me an intuition I have had for a long time:
The first step in conscious use and understanding of language is being able to recognise the use of rhetorical devices. It's like knowing your tool box: a screwdriver would just be an oddly shaped stick if you didn't recognise it and be able to visualise its use (the rhetorical techniques I am using here are 2nd person to create immediacy and analogy to use a familiar example to illustrate the importance of a point). Likewise with language. Explaining the function of rhetorical devices has been done very well elsewhere, such as the top 20 figures of speech at grammar.about.com.