Possible Clues:

• Eastern travellers brought back a not unusual language
• Unusually neat prose nobody speaks, naturally
• Language in which plurals are formed by adding -oj
• In agitation, present a ring, making special speech
• Repeats no sort of lingua franca
• No repeats in an artificial language
• Pert nose with a cheeky tongue
• Stifling communication in the end, doctor operates — words rarely spoken
• Language exercises adopted by new senator
• Fourth letter in Oscar Peterson's made-up language