Hello,
The object '<name>' not found error usually happens when you have not defined a variable and are then using it in a function. SO try and look through your code and see if there is one called 'lang'. If not, this might be an error within a package you're using and they have to update their code.
#Error
print(myText)
#> Error in print(myText): object 'myText' not found
#Fixed
myText = "hello"
print(myText)
#> [1] "hello"
Created on 2022-05-30 by the reprex package (v2.0.1)
Hope this helps,
PJ