John Calvin Commentary 1 Corinthians 14:28

"but if there be no interpreter, let him keep silence in the church; and let him speak to himself, and to God." — 1 Corinthians 14:28 (ASV)

Let him speak to himself and to God. "Let him enjoy," he says, "his gift in his own conscience, and let him give thanks to God." For in this way I explain the expression to speak to himself and to God, as meaning—to recognize in his own mind with thanksgiving the favor conferred on him, and to enjoy it as his own, when there is no opportunity to bring it forward publicly. For he draws a contrast between this secret way of speaking and speaking publicly in the Church—which he forbids.