From the CT Department of Motor Vehicle guidance on the International Driver Permit (IDP):
Students and Visitors to Connecticut:
Connecticut permits a student or visitor to operate a motor vehicle in Connecticut for a period of up to one year with their foreign license. If the license is in a language other than English or Spanish, the license must be accompanied by an IDP (International Driver’s Permit) which serves as an English translation of the foreign license. An IDP can only be obtained in the country which issued the actual incense. An IDP is not considered a valid license and must accompany the valid foreign license.
Note: Out-of-country licenses are not acceptable as a form of identification.