All human languages are mutually comprehensible through a prolonged exposure (‘full immersion’) to their speakers, from a couple of days or weeks to at most a couple of months.
Thus, in the Bloomfieldian scheme, such languages in question are dialects of language (that is, ‘language with no article in front of it’), meaning the biological capacity of the Homo sapiens sapiens for language (speaking). This aforesaid capacity for language is actualized by human groups in a variety of manners, conventionally dubbed as presumably discrete ‘languages’ in the Graeco-Romano-Judaico-Islamic West. Most of these languages appear to the educated (literate) person as radically different on the account of different writing systems. But writing is none other than a technology of graphic representation of some elements of language; this technology is not part of language. This obstacle removed from the path of reasoning about languages, the latter become ‘visible’ (perceivable) to the observer’s eye (or rather, ear) for what they are, namely, non-discrete (that is, continuous) and essentially arbitrary actualizations (artificats) of (the biological capacity for) language within the confines of inherently fluid, interacting and constantly changing groups of humans. A hypothetical extraterrestrial visiting Earth, most likely would see human languages as a single all-human language. From the vantage of such an extraterrestrial, the Humans (Earthlings) speak none other but the single tongue of Humanese (Earthese or Terran).
April 12, 2017