In Suetonius's Life of Claudius 42 we read:
Nec minore cura Graeca studia secutus est, amorem praestantiamque linguae occasione omni professus. Cuidam barbaro Graece ac Latine disserenti: "Cum utroque," inquit, "sermone nostro sis paratus"; et in commendanda patribus conscriptis Achaia, gratam sibi provinciam ait communium studiorum commercio; ac saepe in senatu legatis perpetua oratione respondit.
I'm not sure about the exact meaning of the phrase communium studiorum commercio. The Loeb translation of this passage runs:
He gave no less attention to Greek studies, taking every occasion to declare his regard for that language and its superiority. To a foreigner who held forth both in Greek and in Latin he said: "Since you are ready with both our tongues"; and in commending Achaia to the senators he declared that it was a province dear to him through the association of kindred studies; while he often replied to Greek envoys in the senate in a set speech.
But that's not clear to me either. What is "the association of kindred studies"? The studies are presumably Claudius's studies of Greek, but what or who are they kindred (communes) with and what is the "association" (commercium)?