all three options are grammatically correct and can be used interchangeably. However, I would personally use "related to languages" or "connected with languages" in this context.
"I want my future job to be related to languages" implies that the job is associated with languages or has something to do with them.
"I want my future job to be connected with languages" also implies a relationship between the job and languages, but it may suggest a stronger connection or dependence on languages for the job.
"I want my future job to be linked with languages" is also correct, but it may not be as commonly used as the other two options.
In summary, any of the three options would be grammatically correct, but "related to languages" or "connected with languages" would be the more common choices in this context.