Learn Farsi: یک شخص ساکت می‌تواند بسیار عاقل باشد.

Both words follow the Fâ'el (C1-â-C2-e-C3) morphological pattern we are currently learning, which creates adjectives or agent nouns from three-letter roots. sâket comes from the Arabic root S-K-T (silence), meaning "one who is silent." 'âqel comes from '-Q-L (intellect or reason), meaning "one who possesses reason" or "wise."

Since the Fâ'el pattern makes "doer" nouns, can sâket and 'âqel be used as standalone nouns instead of adjectives?

Yes! Because the pattern translates to "one who does or is," a word like 'âqel can stand alone to mean "a wise person" and can even take plural endings. In this specific sentence, however, both sâket and 'âqel are functioning purely as adjectives describing shakhs (person).

Why is the verb "to be" written as bâshad instead of the standard ast?

This is a necessary change triggered by the modal verb mi-tavânad (can / is able to). In Farsi, the second verb in a chain following a modal must be in the subjunctive mood. You are literally saying "A quiet person is able that they be very wise," which requires the present subjunctive bâshad rather than the indicative ast.

Why use yek shakhs instead of attaching the indefinite -i to make shakhsi?

Both are grammatically correct ways to say "a person." However, using yek before the noun without the indefinite suffix -i often makes the statement sound a bit more general, categorical, or proverbial. It translates slightly closer to "one (type of) person," which fits the philosophical tone of this sentence perfectly.