* Data limitations: We don't have comprehensive data on all languages. Many languages, especially smaller, indigenous ones, haven't been thoroughly documented or studied.
* Defining "least spoken": It's unclear whether we're considering the number of speakers, the number of areas where it's spoken, or the number of native speakers.
* Language families and dialects: Some languages are considered "minor" dialects of larger languages, making it difficult to define them as separate entities.
However, some languages are considered to be among the least spoken, with very small numbers of speakers:
* Akkadian: An ancient Mesopotamian language with only a few speakers who are linguists or scholars.
* Ubykh: A language spoken in the Caucasus region that went extinct in the 1990s.
* Ainu: An indigenous language spoken in Japan, with fewer than 15 speakers remaining.
* Tabiti: Spoken on the island of Tabiti in the South Pacific, with only a handful of speakers.
It's important to note that the number of speakers of many languages is declining due to factors like globalization, assimilation, and the disappearance of traditional cultures.