The International Dunhuang Project has an enjoyable post about phrasebooks “popular with travellers on the Silk Routes in the first millennium AD”:
For example, Pelliot chinois 5538 is a scroll with a series of phrases in Sanskrit and Khotanese, on the general theme of pilgrimage. Some of the phrases form conversations, like the following:
And where are you going now?
I am going to China.
What business do you have in China?
I’m going to see the bodhisattva Mañjuśrī.
When are you coming back?
I’m going to China, then I’ll return.
The conversations also cover practical matters:
Do you have any provisions for the road?
I do not like my provisions.
I’ll go with one or two horses.
There are more examples and a short bibliography if you want to learn more.
And while we’re on the subject, Christopher Culver has a post on “Guides to little-known languages from the French publisher L’Harmattan”; if you read French and have any interest in little-known languages, you’ll want to bookmark it: “If you are interested in the Finno-Ugrian or Turkic world, you can enjoy Yves Avril’s Parlons komi or Saodat Doniyorova’s Parlons karakalpak. The best (well, usually the only) guides to West African languages are written in French, and L’Harmattan covers this part of the world with such titles as Parlons baoulé (Ivory Coast), Parlons éwé (Togo) and Parlons mooré (Burkina Faso).” (Book links at Culver’s post.)