What advice does Tranio give Lucentio regarding his studies? How does Shakespeare help his audience recognize Tranio's intelligence and education, even though Tranio is clearly Lucentio's servant?

The older servant (Tranio) gives Lucentio wise advice to vary his studies, working hardest at what he likes best, "No profit grows where is no pleasure ta'en: in brief, sir, study what you most affect." This advice comes from obvious experience in both life and, to a certain extent, academics. Shakespeare has often had servants impart wisdom to their older masters (like in As You Like it). Shakespeare knew that wisdom and knowledge was not unique to the rich.