As you know, I have been posting a translation, done long ago, of St. Augustine's De dialectica. Not wishing to make too great a schnitzer, I have been looking at some of the other translations, and perhaps we can profit from what I have noted.
1. First rule of translation: make sense. All the translators, even Jean Collart, (Varron, grammarien latin (Paris: Belles lettres, 1954), pp. 280 f.), whose knowledge of Latin is bound to exceed mine, when faced with the derivation of `foedus' from `foeditas porci', translate this with something like `l'air affreux du porc'. Well, pigs may be disgusting, but they are not particularly frightening.
2. Second rule: perform your introtextual tasks first. Maybe Augustine mentions it somewhere else. This, of course, he does just a few lines later, "foedus, per quem foedus efficiatur." The `pig' which enforces a treaty is obviously a military something, and we have not far to look to find this: E.G. McCartney, Figurative uses of Animal Names in Latin and their Application to Military Devices (Lancaster, Pa.: New Era Printing Co., 1912), pp. 36 f., but, as Augustine would say: quis enim egeat auctoritate in re tam perspicua? A pig does not enforce a treaty, an army does.
3. The same Jean Collart renders the aeris tinnitus in the same passage as bourdonnement de l'air. Fourth rule (including the make sense rule): watch out for schoolboy schnitzer: aeris can mean `of brass' as well as `of air'. Also watch out for St. Augustine's knowledge of the Bible and his penchant for using it as his intertextuality, not quoting it, but reflecting it. 1 Cor. 13, 4 (aes sonans aut cymbalum tinniens) comes immediately to mind, so that `aeris tinnitus' has to be `the clanking of brass' (what does brass do?). Also, when it comes to `stridor catenarum', one is forced to think of the `fletus et stridor dentium' of Mt. 8.12, Luke 13.28 and all over the place. I frequently put it on the exams I hand out.
4. Nobody handles `dicibile' right. It is a central part of Stoic doctrine, in the Greek lekto/n (accent on last syllable). One even notices people who ought to know a Greek word formative device, and who will always render an `aistheto/n' as `the sensible, sensibile', rendering `lekton' as `said', even when it makes no sense. `dicibile' means `the sayable'. A remark in passing: until about the 12th century, we did not have a `the' in Latin to render such ideas as `the good'. In that century it became common to use Greek `to' (to bonum `the good') or even French `ly' (ly bonum `the good'), though the use of `to\' goes back somewhat earlier. xth rule (I lost count): Embed it in its tradition. Now that I have complained about my translating colleagues, I am sure you will find I have sinned against all these rules in my own translation of the De dialectica. Nemo sine crimine.