Could Russian replace English as a lingua franca after the 2ACW?
The rise of English as a global lingua franca IOTL was due to the political, cultural and economic strength of Britain and America. The Anglophone nations have suffered significant decreases in their influence, with the US crippled by a bloody, nuclear civil war and balkanized for the foreseeable future, with the UK, Canada and Australia Soviet allies who probably use English with other but Russian with the Russians, and South Africa a radioactive wasteland.
One might take a look and say that even if the English-speaking nations of the world were destroyed, the language might prosper in the Third World where large numbers of people speak it as a second language. However, these nations are isolated, as in the case of West Africa, subordinate to some other non-Anglophone bloc, such as the Phillippines, or completely balkanized and destroyed like India.
In conclusion, English-speaking countries will continue speaking the language and may continue as a lingua franca between these nations, but will not have the pull of English. This raises the question: What language will replace it?
Russian is the most obvious candidate, with the USSR the heart of an Eurasian alliance stretching from the UK to North Korea, from Finland to Iran. Given the position of dominance, the USSR can start with promoting Russian as a second language, much like how China promotes Mandarin through Confucius institutes. Once enough countries speak it as a business language, they will begin to use it as a lingua franca in mass media contexts and other means. Even with the arrival of the *Internet and personal computers, inputting Russian won't be much of a problem if Russian developers use some romanization system like the GOST system devised by the USSR, or use diacritics probably supplied through input mechanisms from the languages of Europeans who devise PC keyboard layout in the first place.