An instant messaging translation plug-in interacts with an instant messaging program to intercept incoming messages and forward these messages to a language translation service. The plug-in then displays a translation received from the service along with the original message. This provides translation which can be used by instant messaging users to communicate across language barriers, and without local translation or knowledge of the internal workings of the translation services used. Additionally, the translation plug-in also provides for manual translation of messages, which allows communication with users who use a different language but do not use the translation plug-in. Messages are modified before translation in order to correct spelling, to prevent particular words or phrases from being translated, and to change instant messaging language into standard language form. The techniques can be performed on various messaging services, including instant messaging on computers or mobile devices, as well as SMS.