Language is, primarily, a verbal activity.
The written layer was added much later.
That's why isolated tribes have verbal language.
But not a written one.
The fundamental premise of learning language via written conversation is, IMHO, a bit shaky.
Found that too learning French that once I got enough proficiency to read was really useful in the amount/style of French I could expose myself to and helped me push up past a plateau of confidence in my spoken French (though not fluent still, so just IMO, take that for what it's worth!)
i learned english to a significant degree by simply conversing with ppl on the internet and watching tv shows/movies in english
for me something like this would be tremendously useful