"But I, as a deaf man, don’t hear. I am as a mute man who doesn’t open his mouth" (38:13). Why doesn't the psalmist answer those who speak against him?

The psalm doesn't say it in so many words. The next verse but one begins "For": "For I hope in you, LORD. You will answer, Lord my God" (38:15). He doesn't answer; he says the LORD will. The psalm doesn't say whether he could have answered, and says of his enemies' words only that they "speak mischievous things, and meditate deceits all day long" (38:12). The next psalm has its own silence, with another reason: "I was mute. I didn’t open my mouth, because you did it" (Psalm 39:9). In Hebrew didn’t open my mouth there has the verb and noun of 38:13's doesn’t open his mouth. Each psalm gives its own reason, and these notes don't join them.