「草の葉メソッド」は、翻訳ソフトを語学学習の中心に組み込んだメソッドである。その翻訳ソフトの進化と成長を熱望していたが、ChatGPT──Generative Pre-trained Transformer(生成可能な事前学習済み変換器)の登場は、その進化と成長を加速させるものだ。どれほど進化し成長しているか、検証してみよう。

次のような一文がある。
 ベネツィアの古書店から始まった「本が本を連れてくる」旅は、じつは「人が人を連れてくる」人情の旅であり、「好奇心が好奇心を呼び起こす」知の冒険であり、偶然とは思えないような出会い、その高揚感、そして迷宮のような謎と宝物のような言葉に溢れている。幸せな人生に必要なものがぜんぶつまっているような一冊だ。こんな豊かで濃厚な経験が2000円足らずで、しかも寝ながらできるなんてやっぱり本ほど素敵なものはない。

 
この日本語を『ChatGPT』に転換させると、

The journey that began at a historic bookstore in Venice is actually a journey of human emotions, where "curiosity begets curiosity" and knowledge becomes an adventure. It's filled with unexpected encounters, the exhilaration that comes with them, and words that are like mazes and treasures. It's a book that contains everything necessary for a happy life. Such a rich and intense experience can be had for less than 2,000 yen, and can be enjoyed while lying down. Truly, there is nothing as wonderful as books.

「もう一度翻訳して」と催促すると、『ChatGPT』はさらなる英文を打ち出した。

The journey that began at the antique bookstore in Venice was actually a human journey of bringing people together. It was an adventure of knowledge where curiosity begets curiosity. It was a journey full of chance encounters that seemed almost too good to be true. It was a journey filled with excitement and a maze of mysteries and treasures in the form of words. This book contains everything necessary for a happy life, as if it were all condensed into one volume. Such a rich and intense experience can be had for less than 2000 yen, and to be able to read it while lying down, there really is nothing as wonderful as a book.

さらに「もっと柔らかい表現にしてくれる」と問いかけると、

The journey that started from a quaint bookstore in Venice is a heartwarming expedition of human connection, where curiosity leads to more curiosity and learning becomes an exciting adventure. It's brimming with serendipitous encounters, the thrill they bring, and words that are like puzzles waiting to be solved or treasures waiting to be discovered. This book holds all the ingredients for a fulfilling life, and what's more, this rich and immersive experience can be yours for less than 2,000 yen, and enjoyed while snuggled up in bed. There truly is nothing quite as lovely as a good book.

さらに「中学生が理解できるようなやさしい英語にして」と催促すると、

This is a story about a journey that began in a really old bookstore in Venice. It's not just any journey, but a journey that teaches us about the importance of curiosity and learning new things. Along the way, there are surprising meetings with interesting people, and discovering words that are like puzzles or treasures waiting to be found. This book has everything we need to live a happy life, and it's not expensive at all, only about 2,000 yen! Plus, we can enjoy it while lying in bed. This story reminds us that books are really amazing!