The phrase "deepen a subject" is correct and usable in written English.
You could use it when describing a topic that you are exploring in greater detail. For example: "This course will provide students the opportunity to deepen their understanding of the English language."
"To restore the human subject at the centre — the suffering, afflicted, fighting, human subject — we must deepen a case history to a narrative or tale," he wrote.
They read articles to help them deepen their understanding of a subject or have dinner with other like- minded individuals.
After four years of working in the field as a professional lawyer, I was itching to deepen my knowledge in a subject area that I loved.
Alternatively, you might tutor students online on a one-on-one basis to deepen their understanding of a subject.
I look at a story as a way of deepening my understanding of a subject.
Gove is keen to encourage teachers to deepen their subject knowledge, and speaks admiringly of the way a subject specialist can escape from the script when giving a lesson: "Take them down little highways and byways and then take them back to the task in hand".
As an artist, he had deepened his subject, moving to a more varied cast of characters and a sense of place — and, above all, toward deeper feeling, a more tragic voice.
New teachers can take classes to deepen their subject knowledge, and receive one-to-one consultations from more experienced educators.
The conversational narrative will certainly deepen a reader's understanding of humans who, over evolutionary time, are subject to the pressures of natural selection.
Applying what is learned in one context to a different situation in a different context has also been shown to deepen a student's understanding (Bransford et al., 2000) and engagement (Zhao and Kuh, 2004) with the subject.
Sutton's reaching for such a high estimate of his subject's historical importance slights the aspects of her personal story that would feed and deepen a psychological portrait.
