Nunc (adv.): now; as it is. Enim (particle): for, indeed. Quantus/ quanta /quantum (1/2, interrog. adj.): how great? how much? Dēmentia, dēmentiae (1f): madness, insanity. Est: is. Hominum is the genitive plural form of homō, hominis (3m): man, human. (For as it is, how great is the madness of humans!)
Turpissima is the neuter accusative plural form of turpissimus/turpissima/turpissimum (1/2): ugliest; vilest, most disgraceful, most shameful; it’s the superlative form of turpis/turpis/turpe (3): ugly; vile, disgraceful, shameful. Vōta is the accusative plural form of vōtum, vōtī (2n): vow; prayer; desire, wish. Dīs is the dative plural form of deus, deī (2m, irreg.): god. Īnsusurrant is the third person plural form of īnsusurrō, īnsusurrāre, īnsusurrāvī, īnsusurrātum (1): to whisper. (They whisper the most shameful prayers to the gods. . .)
Sī (conj.): if. Quis /qua/quid (indef. pron): (in some clauses, especially after sī, nisi, num and nē) anyone, anything; someone, something. Admōverit is the third person singular future perfect form of admoveō, admovēre, admōvī, admōtum (2): to move to; bring nearer; (with aurem) lend an ear. Aurem is the accusative singular form of auris, auris (3f): ear. Conticēscent is the third person plural future form of conticēscō, conticēscere, conticuī, — (3): to fall silent. (. . . if anyone brings an ear, they will fall silent.)
Et (conj.): and. Quod is the neuter accusative singular form of quī/quae/quod (rel. pron.): who, which, that, what. Sciō, scīre, scīvī/sciī, scītum (4): to know. Hominem is the accusative singular form of homō, hominis (3m): human, man. Nōlunt is the third person plural form of nōlō, nōlle, nōluī, — (irreg.): to not want, be unwilling, refuse. Deō is the dative singular form of deus, deī (2m, irreg.): god, deity. Nārrant is the third person plural form of nārrō, nārrāre, nārrāvī, nārrātum (1): to narrate, report, tell. (And what they don’t want a man to know, they tell to god.)
Vidē is the singular imperative form of videō, vidēre, vīdī, vīsum (2): to see. Ergō (particle): therefore, then. Nē (conj. , with subjunctive): that not, lest; after vidē the translation can sometimes be whether/if. . . not. Hic/haec/ hoc (pron.): this; he, she, it. Praecipī is the passive infinitive form of praecipiō, praecipere, praecēpī, praeceptum (3, –iō): to take in advance; advise; order, command. Salūbriter (adv.): wholesomely, healthfully. Possit is the third person singular subjunctive form of possum, posse, potuī, — (irreg.): to be able, can. (See, then, whether this might not be able to be advised healthfully. . .)
Sīc (adv.): thus, so, in such manner. Vīve is the singular imperative form of vīvō, vīvere, vīxī, vīctum (3): to live. Cum (prep.): with (takes the ablative). Hominibus is the ablative plural form of homō, hominis (3m): man, human. Tamquam (conj.): as if (with subjunctive). Sīc. . . tamquam = so. . . as if; i.e., in the manner that you would if. Deus, deī (2m): god. Videat is the third person singular subjunctive form of videō, vidēre, vīdī, vīsum (2): to see. Loquere is the singular imperative form of loquor, loquī, locūtus sum (3, deponent): to speak. Deō is the ablative singular form of deus, deī (2m): god. Hominēs is the nominative plural form of homō, hominis (3m): man, human. Audiant is the third person plural subjunctive form of audiō, audīre, audīvī/audiī, audītum (4): to hear, listen (the verbs are subjunctive because they’re in conditional clauses of comparison introduced by tamquam). (So live with humans as if God were seeing; so speak with God as if humans were listening.)