1. Employers don’t train on languages/frameworks. In most circumstances employees are expected to learn on their own or from a prior employer before applying for a job. Worse, the last place I interviewed only asked about learning from the current employer while never asking about self learning outside the office.

2. Employees, in many cases, believe they can cheat learning by using a tool or framework. That is largely due to a lack of boundaries and experience in a given environment or platform resulting in low trust of peers and the technology.

If you want to require learning then provide sufficient learning material expecting a predefined structured outcome.