I have been managing the long-term correspondence between the American secondary school students and mine for more than 16 years through a “snail mail” as they call it in the USA.
My senior Ss (grades of 9-11) were penpalling with Salt Lake City, Utah, Thonas Jefferson Junior High school Ss , and my so-called “juniors” (grades of 6-7-8) were exchanging letters with the 5-6 graders of Kendall Elementary school, Mount Baker, NY.
I have witnessed how profound was the input in English language skills overall and the motivation to learn English was strong enough. To arrange and manage the correspondence was messy, bothering, hard and time-consuming, though. We exchanged letters twice a year only.
Unfortunately, my two dearest and faithful American colleagues have retired last year and we don`t have any penpal at the moment. It`s too sad, of course.