It seems also that it would be somewhat valuable for the translation work to be what "authentic" Greek, that is, Greek from actual sources from the first century. In a NT Greek class, that would naturally mean primarily, if not exclusively, the New Testament itself.
and Stephen Hill wrote
I agree that there's no substitute for reading authentic Greek
The proposition that new learners of Koine need to only read 'authentic Greek' is a straw man. In the long term, intermediate-advanced learners want to read Greek, with all its odd sentence frontings and odd sentence structures. So the proposition that a person needs to read 'authentic texts' is a valid argument, but the proposition is not true in beginning stages. When a native Greek speaker speaks to their child, does she/he speak 'authentic Greek?' Yes. Is there any text ancient text which limits itself to certain forms, or language complexity or which we would call 'Baby Greek'? No. If you would transcribe the speech of a mother to her child, you would not find any Greek text which matches that limitation of vocabulary and form.
Could a beginning Koine primer put together a bunch of simple sentences from 'authentic sources' which match the structures in any given traditional grammar-translation beginning Koine primer? Yes. The best such grammar giving 'authentic examples' is Croy's primer which has many, many quotes from the NT and LXX demonstrating the structures taught in any given chapter. But the problem with disconnected unrelated sentences is that they are boring and lose the readers interest. The Compelling Input hypothesis (Stephen Krashen) states that to acquire a language, the learner needs 'compelling input' so that they forget they are learning a language because they are so involved in the narrative. The stories of Athenaze and JACT and Hale's Let's Study Greek are compelling Greek. And while those texts are only written texts, and do not involve interactive speaking, they still engage the student more than a list of sentences, which is the way that many NT grammar-translation primers do [ this includes almost most NT beginning primers].
But here is the problem with the premise that you need to only read 'authentic' Greek. One of the tenets of the grammar-translation (GT) approach of teaching is that one start early on reading advanced texts. But the GT approach teaches by structures, usually a complete paradigm of a structure, so there is an innate conflict happening in that approach. So a student taught via this method will not be able to read advanced texts till well into the end of the year. When you look at a mother's speech, the first speech, to her child, she does not take into consideration language structures. When she speaks to her child, she has no concern for "I'm teaching him/her 'o' nouns. I'm teaching my child 'alpha-eta' nouns." She is concerned with getting her child to understand the most basic of meanings. So the question is this: Does a new second-language adult learner [a learner of Koine] need to learn structures in a progressive and pre-deterimined progression, where the input is limited by form constraint, or should he/she learn [learn = acquire the Greek language] by meaning, where there is no need to teach out a complete paradigm in each lesson? (This is the approach which is taught by the living-language-communicative method).
There are some very simple Greek ancient texts (1, 2, 3 John, The Tablet of Cebes, The Gospel of Mark). But the problem is that when one picks up a text, one gets the whole range of forms and structures. The beginner is not ready for that range. Funk's Beginning-Intermediate Grammar of Hellenistic Greek
is an inductive study. Funk systematically goes through texts from John and other easy passages and tries to get the reader to understand what is going on under the hood. But there is not enough exposure to texts in Funk for the reader to 'acquire' the language. Dobson's Learn New Testament Greek
is also an inductive study. Dobson is full of diglott English/Greek passages - it has a plethora of similar, not identical structures which are repeated numerously throughout the book. Dobson rewrites passages and limits the range of forms -- what he does not have is a compelling story like JACT or Athenaze. An intriguing narrative such as found in Athenaze or JACT allows a learner to 'forget they are reading a second language, and become so involved in the second language [not their native language] that they forget in which language they are reading/thinking.
So back to the proposition that learners only need to read 'authentic Greek.' The proposition is that only unadapted ancient texts can convey sentence structure, idiom, vocabulary nuances, etc. It has been proven that the learner has to have a combination of reading and other input (IMHO spoken input/output) in order to acquire a second language. Vocabulary is best gained by reading a massive amount of texts. This is a tenet of modern SLA (Second Language Acquisition) theory. Forms/Structures need to be drilled not by lone instances, or memorized in serial sequence, but learned by being put in context with meaning which is self-evident or understood. The only way to get a student to acquire Greek is to 'drip' forms to them in a meaningful context. The forms must be dripped with enough frequency that there is really no conscious thought attached to the form. That level of frequency is hard to attain via a written-only methodology. Athenaze and JACT are the closest to providing compelling written-only input. I might also add that Paula Saffire's Ancient Greek Alive
also contains a lot of compelling stories. As does C. Peckett's Thrasymachus: Greek Through Reading
. But note that other than Hale's Let's Study Greek
, there is no Koine primer which takes the graded reader approach.
I don't know if there were ancient children's books. If there were any, they were not preserved. I'm sure Homer's works were the mainstay of classical education. Homer is compelling. Nowadays, we don't call children's books 'graded readers,' but that is what they really are. But children's books do not have the intellectual complexities that adults require - and thus most adults may find Dr. Zeus' in Koine Greek rather monotonous. And that's where graded readers of ancient Greek fill the gap. I hope this brings some additional issues and answers to your question. (Note: There are a number of Attic primers which I really need to analyze further - to be fair to all authors).