All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is not permissible to use a forbidden means such as watching forbidden movies or other forbidden things to learn the language or other permissible things.
However, learning the language through a forbidden movie does not necessitate that it is prohibited for the person to benefit from the language that he has learnt.
Likewise, using the phone, for example, in a forbidden matter, does not necessitate the prohibition of what a person has benefited from through that phone.
What is forbidden does not make what is lawful forbidden.
This is very clear and doubting about it is nothing but dispraised whispers.
It is permissible to view lawful materials on platforms that display permissible materials and the like, as long as the person does not fall due to that watching into forbidden watching or hearing.
Allah knows best.