you certainly give

Paul is speaking to the Corinthians as if they were one person, so the word "you" here is singular. (See: rc://en/ta/man/translate/figs-you)

the other person is not built up

Building people up represents helping them become mature and strong in their faith. This can be stated in active form. See how you translated "builds up" in 1 Corinthians 8:1. AT: "the other person is not strengthened" or "what you say does not strengthen any outsider who might hear you" (See: rc://en/ta/man/translate/figs-metaphor and rc://en/ta/man/translate/figs-activepassive)