WHAT IS AN EXOTIC LANGUAGE?

Alexander Argüelles´s hobby is language learning. He has studied over 60 of them and he dedicates his life to the vocabulary and grammar of "exotic languages." I read that he considers "Arabic" and "Korean" exotic languages. Would we be correct in thinking that Koreans and Egyptians do not know their language is "exotic." What is an "exotic" language? Those that have no affinity with ours? Non-European languages? Most African languages and dialects can be considered "exotic" viewed from our linguistic vantage point. However, for a speaker of Bambara or Fula, English could be an "exotic language." For a speaker of Guaraní, Spanish grammar must be "exotic." My dictionary defines "exotic" as unusual or strange, in which case all languages are. Fancy that.