In redesigning the Modern Physics Lab at Strive University, we focused its purpose on developing writing skills. In doing that, we implemented the pedagogical method Letters Home, which offers students the ability to practice communication in the form of letters to experts and non-experts. Students were additionally tasked with writing traditional lab reports. This case study investigates 6 students' completion of 6 writing assignments (letters and reports) to a real audience. We used the AAPT guidelines to develop a qualitative coding scheme with 8 categories, and we used a linguistic analysis software program called LIWC to evaluate the assignments' authenticity, clout, tone, and analytical thinking. Our results indicate 6 of the 8 coding categories appear in at least 50% of the data. Also, letters to experts and non-experts indicated similarities in analytical thinking. Authenticity scores were higher for letters to non-experts than experts. Overall, letters and reports are similar in terms of both the AAPT-inspired codes and linguistic dimensions probed by LIWC. The similarities between the letters and lab reports from our study may be due to our curriculum redesign.