There are grammatical errors even in his silence.

Lec’s aphorism turns “silence” into a kind of utterance that can still betray a person’s deficiencies. The joke depends on treating grammar—normally a property of speech and writing—as something so deeply ingrained (or so conspicuously lacking) that it shows even when someone says nothing. It can be read as a satire of pedantry (the speaker is so judgmental that he “corrects” silence) and, more pointedly, as a jab at intellectual pretension: some people’s attempts at dignity or restraint are undermined by the clumsiness of their thought. The line also fits Lec’s broader skepticism about language and authority, where even absence of words can be revealing.