Answer:
The decline in the use of native language by the Chulym people as well as the adoption of Russian as their primary mode of communication can be attributed to the implementation of "the second mother tongue policy" under the rule of Joseph Stalin. Under this policy children of Chulym (and other native) people were sent to schools where they learned Russian and were also restricted from using their language. This created a negative image of the Chulym language. In the movie, The Linguists, Vasya, a Chulym native speaker, said that, “Chulym was viewed as a ‘gutter language’,". Another noteworthy reason was that, in the decade of 1970, the Chulym people were forced into colonies where Russian was the primary language.
There are several different reasons depending on the perspective you look at it.
If you're looking at it from the government perspective, then this was due to the fact that they wanted to get rid of the tradition and have a complete take over of the culture by getting rid of it.
Other explanations are that they wanted to switch an alphabet or genuinely wanted to simplify the actual characters.
Hope this helps!
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