[ThomasWinwood]

The pronunciation used in schools for didactic purposes has only a modest relationship to authentic historical pronunciation. Pronouncing eta as [i] is an influence from modern Greek - in ancient times it was [ɛː], as described by the author (and as used in my secondary school Ancient Greek class - when we switched teacher to one who pronounced it [i], he conformed to our standard rather than vice versa). The bLogicarian has an article [1] which goes into more detail with some recordings, or you can pick up a copy of Vox Graeca by W. Sidney Allen.

[1]: https://blogicarian.blogspot.com/2012/10/ancient-greek-food-...