Technique to find first principal parts when later parts change spelling? E.g. find 'nanciscor' from 'nactus'

Question

I am tutoring a friend who is preparing for a graduate school translation exam, of the "unseen passage, dictionary allowed, time limit imposed, be accurate" variety.

We came across nacti in paragraph 22 here. I found nanciscor pretty quickly, and she didn't.

When I tried to explain how I knew to check that spelling, I was at a loss.

Here's my real question: Is there any sort of good procedure I could give a student that would allow them to make a list of probable first principal part spellings, given later principal parts?

Answer 1

To be able to generate a list of candidates, one should know some common ways to produce different principal parts from a given stem.

To produce the present stem (the first principal part as you call it) one might add a nasal before the last consonant. To produce the perfect stem one might reduplicate the first syllable, with possibility for vowel gradation. To produce the perfect participle stem one might add a t, with possibility for assimilation in the preceding consonant. Using these rules to the stem tag-, one obtains the stems tang-, tetig- and tact-.

You can find more possible ways to play with the stems in many Latin grammars, and I will not attempt to list them here. Instead, let me try to detail the process I would take to find nancisci from nacti. First, the perfect participle stem seems to be nact-. There is no sign of reduplication (we couldn't remove a syllable anyway since there is only one — and reduplication should only appear in the active perfect stem anyway), so the present stem might be nac-. It is possible that the t has caused some assimilation, so it could be nag- or nah- instead. There could also be a nasal in the present stem, so also nanc- and nang- might be possible. If you manage to conclude that one option is nanc-, you will find the verb in a dictionary; you won't need to guess the incohative -isc-.

In short: To see the first principal form, know the rules to generate later principal forms and try to guess which ones may have been used. If I see a perfect participle of a new verb, I will not know the first principal part for certain, but I can make a number of guesses. And know your irregular verbs — they may also come with prefixes.