If an employer determines that English competency is a business need, at what point can...

For new hires, employers can include language requirements immediately — but only if they can demonstrate that English proficiency is a business necessity (e.g., safety, communication, customer service).

Extract from HRCI-aligned HR knowledge (Risk Management):

SPHR candidates must ensure “job requirements are defensible under EEOC and Title VII guidelines.” Language must be tied to business necessity, but is permitted for future recruiting efforts with appropriate documentation.