Stephen Krashen (the author of this paper, not the answer to the question)
International Journal of Language Teaching (in press)
On page 49 of his new book, While We're on the Topic, Bill VanPatten writes: "The role of input is often credited to Stephen Krashen. Although Krashen popularized the notion of comprehensible input .... the idea of communicative input has been around longer, and began with first language acquisition. What Krashen distilled for many people ... is this: acquisition happens through understanding messages. In short, acquisition is a byproduct of comprehension..."
VanPatten is correct. In fact, I wasn't even the first person to talk about comprehensible input in second language acquisition.
First language acquisition researchers have indeed talked about communication, but have not explicitly acknowledged the centrality of comprehensible input. Several first language literacy researchers, however, have been very clear about the role of comprehensible input: We learn to read by reading (making sense of what is on the page), and develop other aspects of literacy (vocabulary, writing style, complex grammar, spelling) through reading (e.g. Frank Smith, Kenneth Goodman, Richard Anderson, Richard Allington, Warwick Elley and others), all independent of my work.
Several second language researchers arrived at versions of the Comprehension Hypothesis before I did, including Leonard Newmark, Harris Winitz and James Asher. In addition, both S.P. Corder and Larry Selinker made distinctions similar to the acquisition-learning distinction and hypothesized that acquisition is available to the adult. (1)
I have acknowledged these scholars in several publications, including Krashen (2013).
My thanks to Bill VanPatten for making this point, and for reminding us to honor our lineage and learn from the pioneers in our field.
(1) Those doing research in animal language (animals acquiring their own languages and acquiring human languages) have been vague, even though some of their conclusions appear similar to what is stated in the Comprehension Hypothesis. To my knowledge, only Pepperberg has explicitly related animal language findings to comprehensible input. In Krashen (2013), I review animal language studies from the point of the view of the Comprehension Hypothesis.
Krashen, S. 2013. The comprehension hypothesis and animal language. József Horváth, and Péter Medgyes. Studies in Honor of Marianne Nikolov. Pécs: (pp. 243-258). Lingua Franca Csoport.
VanPatten, B. 2017. While We're on the Topic. Alexandria, VA: American Council on the Teaching of Foreign Languages.