I am finding out about the ancient equivalent to modern foreign language phrase books, used in conversations. Such as a medieval Italian-Latin conversational book, or an ancient English-French learning book.
For example, in Korea, during the Joseon dynasty, there was a Mongolian-Korean conversational book. I don't know the name in English, but the Korean name is mong-uh-no-gul-dae, '몽어노걸대'.
Mostly, there were textbooks for learning the foreign language:
Professor Eleanor Dickey travelled around Europe to view the scraps of material that remain from ancient Latin school textbooks, or colloquia, which would have been used by young Greek speakers in the Roman empire learning Latin between the second and sixth centuries AD...
Textbooks in the Ancient World, lay out everyday scenarios to help their readers get to grips with life in Latin. Subjects range from visiting the public baths to arriving at school late – and dealing with a sozzled close relative.
(source: The Guardian)
Before the development of the movable type printing press there was no such thing as "publication for the mass market". This meant that books were much rarer, and more expensive, than we are today used to.
Also if you are thinking of a modern pocketbook that could be conveniently referred to in a market place, that form factor was not yet seen as generally useful.
Finally, labour costs even for relatively skilled labour were much less than today. For anyone of means sufficient to allow for travel it would have been simpler and less expensive, as well as more functional, to hire a local translator than to acquire a (very specialized) type of book to allow for limited conversation.
However if you are thinking more along the lines of text easily translated, for learning practice, Caesar's Gallic Wars has been derided as such since its origin. It was deliberately written to be easily read to, and by, the lower classes of Rome, and has been used as a Latin Primer ever since. Furthering its attraction, it's a good war story - and with most Classical Scholars traditionally being men and boys, that was a definite plus.
At least one case must have been more of an academic exercise than one with any hope of continuing or teaching the language:
From Wikipedia on Etruscan:
The last person known to have been able to read Etruscan was the Roman emperor Claudius (10 BC – AD 54), who authored a treatise in 20 volumes on the Etruscans, called Tyrrenikà (now lost), and compiled a dictionary (also lost) by interviewing the last few elderly rustics who still spoke the language (emphasis mine)
The 20 volumes are referenced by Suetonius in his Twelve Caesars on Claudius, ch 42.2
At last he even wrote historical works in Greek, twenty books of Etruscan History and eight of Carthaginian. Because of these works there was added to the old Museum at Alexandria a new one called after his name, and it was provided that in the one his Etruscan History should be read each year from beginning to end, and in the other his Carthaginian, by various readers in turn, in the manner of public recitations.
However, I can't actually find a primary reference on this supposed dictionary/vocabulary: all the searches ended up as circular quoting. Happy for someone to provide a source.
There were certainly language phrasebooks in the later middle ages (12th-14th centuries) - common phrases shown side-by-side. Just like phrasebooks today, these were organised by theme. You can see an example here (a 14th-century English-French phrasebook in a manuscript now at Cambridge University Library).
