Nihil (indeclinable neuter noun, here accusative): nothing. Mīrēmur is the first person plural subjunctive form of mīror, mīrārī, mīrātus sum (1, deponent): to be surprised, marvel, wonder (at); admire (subjunctive because it’s hortatory). Eōrum is the m/n genitive plural form of is/ea/id (pron.): he, she, it; this, that. Ad (prep.): to (takes the accusative). Quae is the neuter accusative plural form of quī/quae/quod (rel. pron.): who, which, that, what. Nātī sumus is the first person masculine plural perfect form of nāscor, nāscī, nātus sum (3, deponent): to be born; spring forth. (Let us wonder at nothing of those things to which we have been born. . .)
Quae is the f/n nominative plural form of quī/quae/quod (rel. pron.): who, which, that, what. Ideō (adv.): therefore, for that reason, for this reason, for the reason (that. . . ; here the reason is introduced by quia below). Nūllī is the m/f/n dative singular form of nūllus/nūlla/nūllum (1/2, irreg.): no, not any, none; (m. sg. used substantively) no one—the dative of agent, used with the passive periphrastic to come. Querenda is the neuter nominative plural form of querendus/querenda/querendum (1/2), the gerundive (to be complained about) of queror, querī, questus sum (3, deponent): to complain. (Sunt is implied from the next clause.) (. . . which (are) to be/should be complained about by nobody for this reason. . .)
Quia (conj.): because, (for the reason) that. Paria is the neuter nominative plural form of pār, paris (3, adj.): equal; like, similar. Sunt: they are. Omnibus is the m/f/n (here m) dative plural form of omnis/omnis/omne (3): every; all. (. . . that they are equal for all.)
Ita (adv.): so, thus; yes. Dīco, dīcere, dīxī, dictum (3): to say. Paria sunt: they are equal (see above). (I say so/yes, I say: they are equal.)
Nam (particle): for, because. Etiam (particle): still; even; also, too, as well. Quod is the neuter accusative singular form of quī/quae/quod (rel. pron.): who, which, that, what. Effūgit is the third person singular perfect form of effugiō, effugere, effūgī, effugitum (3, –iō): to escape. Aliquis /aliqua/aliquid (pron.): someone, something; anyone, anything. Patior, patī, passus sum (3, –ior, deponent): to undergo, suffer, endure; allow. Potuit is the third person singular perfect form of possum, posse, potuī, — (irreg.): to be able, can. (For even what someone has escaped, he was able to suffer—i.e., he could have suffered.)
Aequus/aequa/ aequum (1/2): equal; just, fair, impartial. Autem (particle): but, however; and, moreover, and indeed. Iūs, iūris (3n): law, right, authority. Est: is. Nōn: not. Quō is the m/n ablative singular form of quī/quae/quod (rel. pron.): who, which, that, what. Omnēs is the m/f nominative plural form of omnis/omnis/omne (3): all; every. Ūsī sunt is the third person masculine plural perfect form of ūtor, ūtī, ūsus sum (3, deponent): to use, manage; experience; it usually takes an ablative object—here, quō. (And indeed an equal law is not (one/a law) which all have experienced. . .)
Sed (conj.): but. Quī/quae/ quod (rel. pron.): who, which, that, what. Omnibus is the m/f/n (here m) dative plural form of omnis/omnis/omne (3): every; all. Lātum est is the third person neuter singular perfect passive form of ferō, ferre, tulī, lātum (3, irreg.): to carry, bring forth; produce; endure; propose or pass (a law). (. . . but (one) which has been passed for all.)
Imperētur is the third person singular passive subjunctive form of imperō, imperāre, imperāvī, imperātum (1): to command; rule (subjunctive because it’s jussive). Aequitās, aequitātis (3f): evenness; equanimity; equity. Animō is the dative singular form of animus, animī (2m): mind, soul; will, intention. (Let equanimity be commanded to the mind. . .) Et (conj.): and. Sine (prep.): without (takes the ablative). Querellā is the ablative singular form of querella, querellae (1f): complaint. Mortālitās, mortālitātis (3f): mortality; mankind. Tribūta is the accusative plural form of tribūtum, tribūtī (2n): tax, tribute—originally the neuter form of tribūtus/tribūta/tribūtum (1/2), the perfect passive participle of tribuō, tribuere, tribuī, tribūtum (3): to share out; bestow; allocate; ascribe. Pendāmus is the first person plural subjunctive form of pendō, pendere, pependī, pēnsum (3): to suspend, hang; pay out (subjunctive because it’s hortatory). (. . . and without complaint let us pay the taxes of mortality.) (Notice that he uses the language of law and government— aequum iūs, imperō, tribūtum —to suggest the regime imposed by nature.)