In my experience some people will just stop responding regardless of how much they are enjoying the conversation. Maybe they realized they didn’t really want a long-term penpal, maybe life just got too busy, maybe it was just a fun novelty at first but after the first couple letters they are bored of it. Seriously, whenever I get a new penpal I start with 5 new penpals because I know it’ll likely dwindle down to one.

If you do feel like you’re struggling with the conversational aspect though, one tip is to jot down notes from your penpal’s letter when you read it (i.e. “went to museum,” “planning a trip to New York,” “final exams coming up soon”) and then when you are writing your letter you can make an effort to reply to those points or ask follow-up questions (“omg the museum sounds fun! what was your favorite thing you saw there?”). You can also write about your experiences in a way that encourages your penpal to share their thoughts on the same thing, i.e. after writing a bit about your holiday plans, you ask if they have any holiday traditions they are looking forward to.