Noun
sprachbund (plural sprachbunds or sprachbünde)
(linguistics) A group of languages sharing a number of areal features (similar grammar, vocabulary, etc.) which are primarily due to language contact rather than cognation.
Synonyms: area of linguistic convergence, diffusion area, language crossroads, linguistic area
Sprachbund (plural Sprachbunds or Sprachbünde)
Alternative letter-case form of sprachbund.
In sum, the idea was that Turkic, Mongolic, and Tungusic languages form a Sprachbund —the result of convergence through intensive borrowing and long contact among speakers of languages that are not necessarily closely related. Source: Internet
Other classifications of languages Sprachbund main Shared innovations, acquired by borrowing or other means, are not considered genetic and have no bearing with the language family concept. Source: Internet