I was asked to work with a group of young girls whose parents wanted them to get more English than they were getting in school. I began by explaining that I would be making up stories with the girls and playing games, doing things that would be much different than what they were doing in school. As I gave them a brief explanation of the principles of Comprehensible Input, one of the fathers was vigorously nodding his head.
Later he told me his own story. His father was born in Italy, near Venice, came to France as a small child, and grew up bilingual, speaking Italian at home and French in school and everywhere else. When his father wanted to marry, he returned to Italy and brought back an Italian bride who spoke no French. Their first son grew up perfectly bilingual, like his father, speaking Italian at home and French elsewhere.
By the time the second son was born, the mother had begun speaking some French. The family as a whole considered the Italian dialect which they spoke as inferior, and believed that speaking good French was the key to success. When the second son began to speak, his parents and older brother laughed at him, saying he spoke Italian with a French accent. Because he disliked being laughed at, he found it easier to speak French, which everyone encouraged. His parents were proud of how well he spoke French.
He returned to Italy on holiday with his parents a few times, but relied on his parents or brother to translate for him. He understood what was said in Italian, having heard his parents and older brother speak Italian all his life, but could not answer. Any efforts he made to speak were laughed at, so he stopped trying.
He was a good student, took English and Spanish as foreign languages in school, where he did well, and finished with a very good degree leading to a good job in management. He married a French girl and decided to take her to Italy for their honeymoon.
Then he found himself in Italy with no translators around. At first he found it difficult to make himself understood, then words began to come to him. He told me that within three days he was speaking fluent Italian. He said that today he has a slight French accent and occasionally makes mistakes in gender, but has no difficulties in communicating and being understood.
Dr. Krashen considered this story as a demonstration of the efficacy of comprehensible input alone, proving that production is not necessary for acquisition. Production is merely a way to show what has been acquired.