Language Digit or Discriminating Digit - General Recommendations on Telephone Switching and Signalling - Functions and Information Flows for Services in the ISDN - Supplements (Study Group XI) 2 pp
The language digit defined under 0 1.1.5 above indicates the service language to be used between operators in the international service, that is to say, the language to be spoken in the incoming international exchange by the incoming, delay and assistance