Salve! Is there a certain thought process you use when choosing how to form modern English phrases into Latin?
How do you choose which form of a verb/noun to use and decide between a plethora of synonyms?
Those are some good questions.
When I go to render modern English into Latin, the first thing that I do is think about the overall meaning of the English text and then try to think of some corresponding ideas according to the Latin idiom. I almost always consult Meissner’s Latin Phrasebook when I am at the “Latin idiom” stage of the process. This Meissner’s Latin Phrasebook is very helpful because it contains idiomatic Latin phrases (from the works of Cicero, Caesar, Livy, and others) which serve as translations of English phrases and terms which are relevant to many areas of life (e.g., parts of the body, the arts and sciences, and war). Unfortunately, this book is more than one hundred years old, so its usefulness is limited. If I cannot find the right phrase in this book, I usually then go to the Loeb Classical Library’s site and search for the English phrase, and then I see if I can find any place in Latin literature which corresponds to an English translation which contains the phrase. If this does not work, then I consult the latest edition of John Traupman’s New College Latin & English Dictionary, which contains many Neo-Latin terms. If I am still stuck, I look at Meissner’s Latin Phrasebook again to find a phrase which is similar in meaning to what I want to say in Latin and then change it a little to fit my needs. I might instead simply render the basic meaning of the English into Latin, using the “Preliminary Hints” section (comprising the sections “Avoid poetic, unusual, or late words” and “Use words in their normal Latin meaning” and “Translate thoughts, not words” and so on) of Bradley’s Arnold Latin Prose Composition as a guide. Sometimes there are instances where I just translate the English into Latin verbatim because the individual English words appear to be as important to the presentation as the ideas which they express.
Deciding on a particular word among several synonyms is often not too difficult. Latin has many synonyms, but almost none of them are truly interchangeable. (Lumen and lux, for example, might be interchanged in poetry, but that comes about due to poetic license, and there is indeed a difference: lux is light itself and lumen, which has the instrumental suffix -men, is a light source—a luc-men—like a lamp or the sun.) If I have trouble deciding on a particular word, I might consult Dumesnil’s Latin Synonyms or Döderlein’s Hand-book of Latin Synonyms. They are helpful, but again they are more than one hundred years old, so their translations do not always correspond to contemporary English (e.g., they might use the word passion to mean “suffering” rather than “strong feeling or emotion”). When it comes to more modern terms, I typically look at what Vicipaedia, the Latin Wikipedia, has to say about them. I also consult the latest addition of Traupman’s Conversational Latin for Oral Proficiency because this has a large Latin term list near the end. I also search through various other Neo-Latin sources like:
The Morgan-Owens Neo-Latin Lexicon;
Morgan’s Lexicon Latinum;
Lexicon Latinum Hodiernum;
Philosophia Latine Disserenda;
If I find variant translations of something, I decide on a translation according to these criteria:
whether the term is morphologically or syntactically valid according to the formation procedures which the Romans themselves employed (e.g., possestrix is good but the “possessrix” which appears in the Lexicon Latinum Hodiernum is garbage);
whether a variant of a term shows up in more than one of the sources;
whether the term comprises a single word or more than one word;
whether the term employs just Latin word elements or non-Latin elements like those from Greek or the modern Romance languages;
You might wonder how Neo-Latinists create neologisms. The first thing to realize is the fact that Latin is quite adverse to neologisms in general. The Roman writers and their later counterparts have been avoiding the creation of new words. They instead are more likely to write circumlocutions or paraphrases. (Writers are not always as steadfast about avoiding new words as Tacitus is at Annales 1.65 where he avoids calling spades spades, but sometimes they do come close.) Still, there might be times when neologisms are necessary. Fortunately, Latin is robust enough to have several options to coin new words. The options that we have are:
We can take an already-existing word and give it a new meaning (e.g., pellicula, originally “little hide,” but having the Neo-Latin meaning “movie” or “film”).
We can import a non-Latin word into the language and give it a Latin form (e.g., kimonum, from kimono, and the adjective iazzicus, from jazz). The Romans were doing this with Greek words for centuries, as seen in words like philosophia and polypus.
We can use the rules of Latin composition and derivation to create new Latin-form words (e.g., interrete, from inter and rete, for “internet,” and basipila, from basis and pila, for “baseball,” and even caeliscalpium, from caelum and scalpere, for “skyscraper”).
We can look to certain modern languages, like Greek and the Romance languages, to find modern phrases and then invent Latin calques of such terms (e.g., pomum terrestre for “potato,” which is a calque of the French phrase pomme de terre).
I believe what determines which of these to use in a particular situation has to do with the ease through which someone can deduce a neologism’s meaning according to its morphological or syntactical resemblance to modern terms.
Perhaps you noticed that although I create a lot of Latin compound words and derivatives, I rarely use any of them in my actual translations. That is intentional. I am following the typical Latinist procedure of creating and mentioning neologisms only when they are needed while at the same time working primarily with already existing and familiar Latin words. Most of the neologisms that I create exist because they are meant to demonstrate my skills in linguistics and wordsmithery. I want to see how these new words look and sound. And I create these words for fun. When I do my translations, however, I want to make it so that as many people as possible can understand what I want to say without having to rely too much on the idiosyncrasy of my neologisms. I think that anyone who knows how to read Latin should be able to work out the essential meanings of my translations.
Utinam hoc tibi prosit! I hope this is helpful!