Hortative construction (biyâ, biyâyid)

To suggest a shared activity ("Let's do something"), Farsi uses the imperative form of "to come" (بیا or بیایید) followed by the main verb in the present subjunctive (usually starting with بـ). Because you are saying "Let's", the main verb takes the "we" ending (ـیم).

Speaking to One Person (بیا)

Use بیا when addressing one friend or peer.

Speaking to a Group (بیایید)

Use the plural form بیایید when addressing multiple people or speaking formally.

Saying "Let's Not"

To suggest not doing something, keep the introductory "come" verb positive and make the main verb negative (swap the بـ prefix for نـ).