Why do some sources give the principal parts in a different order, or include an extra, fifth principal part?

Question

Many online sources state categorically that ordinary (non-deponent, non-defective) Latin verbs have four principal parts. It is often also implied that they have a fixed order (1st pers. sgl. present active indicative, infinitive, 1st pers. sgl. perfect active indicative, and the supine). Many sources also state that the four principal parts are given in all dictionaries.

But some sources omit the infinitive or place it last. Notably, Lewis & Short lists the principal parts like this: ămo, āvi, ātum, 1. Now, you may say that the 1 effectively tells us the infinitive, and that's true - even so, a conscious choice has been made not to list all the principal parts. And more to the point, the Elementary Lewis & Short lists the forms like this: amō āvī, ātus, āre. In other words, it puts the infinitive last - so the forms aren't in (what is widely considered) the canonical order. ( https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0060%3Aentry%3Damo ) Similarly, if you visit https://logeion.uchicago.edu/amo and tab across to Gaffiot 2016 (a French dictionary of Latin), the principal parts are given as ămō, (6) āvī, ātum, āre - the standard four but in a less usual order.

I know that the canonical order for cases differs between authorities (it was traditionally nom-gen-dat-acc-voc-abl, but many recent grammarians have preferred a different ordering) but I haven't found anything about disputes over (or changes in) the canonical order of the principal parts.

But what is perhaps more surprising is that some sources add an extra principal part. So, if you look in Ernout & Meillet, Dictionnaire étymologique de la langue latine, you see: amo, -ās, -āuī, -ātum, -āre. A fifth principal part (the 2nd p. present singular active indicative) has been added. And this is true of verbs in general; "amo" is merely my example, not a unique case.

Now, English Wikipedia states as fact that Latin verbs (other than deponents etc) have four principal parts, with no indication that there is any dispute or anyone who thinks differently. But if you consult the Italian Wikipedia, it is stated equally categorically as fact that Latin has five principal parts ( https://it.wikipedia.org/wiki/Paradigma_(linguistica) ):

in latino, il paradigma è composto da cinque forme:

1. prima persona singolare dell'indicativo presente attivo
2. seconda persona singolare dell'indicativo presente attivo
3. prima persona dell'indicativo perfetto attivo
4. supino attivo
5. infinito presente attivo

Any idea where the perceived need for the fifth principal part (the second person singular present active indicative form) comes from, or why the ordering varies (has the infinitive historically come second or last, or does it vary wildly)?

Answer 1

The Italian Wikipedia article linked to before now says:

In latino, il paradigma è composto da quattro forme:

1. prima e desinenza della seconda persona singolare dell'indicativo
2. presente attivo prima persona singolare dell'indicativo perfetto attivo (passato remoto)
3. supino attivo (gerundio)
4. infinito presente attivo

Per esempio, il paradigma di scribo (scrivere) è: scribo, scribis, scripsi, scriptum, scribere (scrivo, scrivi, scrissi, scritto, scrivere). Oppure, "portare": fero, fers (1^ e 2^pers.invdicat.pres.), tuli (1^ pers.pass.rem.), latum (supino, gerundio), ferre (infinito); "andare": eo, is, ivi (oppure ii), itum, ire.

This quote thus confusingly now says there are four forms, but describes the first as composed of both the first and second person singular. It then gives examples listing five forms.

As I look at the list, it does seem to make sense to list both the first and second person forms for verbs like fero, fers and eo, is, which are just treated as irregular in the English speaking tradition I am familiar with. This arrangement potentially reduces the number of "irregular" verbs at the cost of creating an additional form to recite and/or memorize for all verbs. From what I quote below from Charisius, this practice also seems to have roots in earlier traditions.

As for the placement of the principal parts, I presume that putting the first-person singular first reflects a partial native tradition of using this form as the citation form. Putting the infinitive last would correspond to the citation form used for modern Romance languages and might act as a way of summarizing the verb forms and using the citation form more similar to what students expected for their own languages, as if English speakers recited: "amō, amāvī, amātus, 'to love.'"

I suspect the other aspects of the ordering simply represent different learning traditions that in turn reflect different logic and different ideas of what is most helpful. This would also vary according to the language in which the Latin was taught.

You can put the infinitive second/third to round out the forms that determine the present tense system or put it last to sum up the common meaning of all the verb forms.

But some sources omit the infinitive or place it last. Notably, Lewis & Short lists the principal parts like this: ămo, āvi, ātum

In a large dictionary like Lewis & Short, I presume economy of space is a major concern, so that forms considered obvious could be deleted.

Any idea where the perceived need for the fifth principal part (the second person singular present active indicative form) comes from...?

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In the 4th c. AD, the grammarian Flavius Sosipater Charisius wrote the following (which doesn't answer my question - unless there is a longer version of the text, which I'll seek out

Here is a fuller text from that author that I see in Eleanor Dickey's Learning Latin the Ancient Way: Latin Textbooks from the Ancient World on pp 93-94 (ordo = "conjugation"):

De ordinibus verborum

Ordines verborum sunt quattuor, qui verba dispertiunt. primi ordinis est verbum cuius secunda persona -as litteris terminatur, velut amo amas. secundi ordinis es verbum cuius secunda persona -es terminatur, velut teneo tenes; terti ordinis est verbum cuius secunda persona per -is correptam terminatur, ut ago agis; quarti ordinis est verbum cuius secunda persona productis -is litteris terminatur, velut munio munis, itaque omnia verba quae eiusdem ordinis erunt similem etiam declinationem habent, et ideo satis est ex quoque ordine cuiusque verbi tam activi quam passivi declinationem per omnia tempora et modos exempli gratia perscribere. nam modi verborum sive qualitates sunt quinque, pronuntiativus seu finitivus, imperativus, optativus, subiunctivus seu coniunctivus, infinitivus. declinantur autem hoc modo.

Declinatio verbi ordinis primi

Verbum finitivum ordinis primi activum termporis instantis numeri singularis amo amas amat et pluraliter amamus amatis amant, praeteritit inperfecti amabam amabas amabat, perfecti amavi plusquamperfecti amaveram, futuri amabo. imperativa instantis ama amet, futuri amato tu, amato ille. optativa instantis et praeteriti inperfecti ut amarem, perfecti ut amaverim, plusquamperfecti ut amavissem, futuri ut amem, subiunctiva instantis cum amem, praeteriti inperfecti cum amarem, praeteriti perfecti cum amaverim, plusquamperfecti cum amavissem, futuri cum amavero. infinita instantis temporis amare, praeteritii amasse, futuri amatum ire, amaturum esse. participia instantis amans, futuri amaturus. supina vel adverbia amandi amando amandum. passiva instantis temporis amor amaris amatur, pluraliter amamur amamini amantur, passiva inperfecti amabar amabaris amabatur, passiva perfecti amatus sum, fui, passiva plusquamperfecti amatus eram, fueram, passiva futuri amabor. passiva imperativa instantis amare ametur, futuri amator. optativa instantis et inperfecti ut amarer, perfecti ut amatus sim, fuerim, plusquamperfecti ut amatus essem, fuissem, futuri ut amer. subiunctiva instantis passiva cum amer, praeteriti inperfecti cum amarer, perfecti cum amatus sim, fuerim, plusquamperfecti cum amatus essem, fuissem, futuri cum amatus ero, fuero. passiva infinita instantis amari, praeteriti amatum esse, futuri amatum iri. participia praeteriti passivi amatus, futuri amandus. passiva inperonsalia amatum amatu. appellatio amatio; nomen amator; adverbium amabiliter. ergo in promo ordine, ita ut praedictum est, secundam personam per -as observabis finitam, ut amo amas, quae a littera per totam declinationem media invenitur, futuri primam personam per bo, ut amabo, optativa em, coniunctiva ro. imperativus modus a litteram habet subtracta s, ut ama; cui inpones re litteras et facies infinitivum, ut amare.

I need to express a few preliminary cautions. I probably have many typos here, but have made some effort to be accurate. There is an additional shorter section (called "De verbo") quoted in Dickey's book describing verbs in general, including a summary of the number of "qualities" (finite and infinite) that determine number, person, tense, mood, etc. and five voices (active, passive, neuter, common, and deponent). I have omitted this section since I see nothing in it explaining the principal parts.

It is striking how much of the quote is like our traditions, but there are numerous deviations from our theory. There are also oddities of order and terminology that might be explained assuming a Greek-speaking audience or at least an underlying model of a Greek verb.

As for the principal parts and their order, the last bit of the quote implies that the second person singular is used to establish the theme vowel for the present and its related forms. In the long list of the forms, the infinitive is also explained last, before a list of other forms that were considered other parts of speech, such as participles, nouns of two types, and adverbs. This ordering might reflect or influence the order of principal parts used in dictionaries, which is not explicitly mentioned anywhere.

Dickey's book also has a sample glossary listing the words beginning with "H." The only verbs I quickly note are listed in one form: habet ("he has"), hittio ("I track") and hospitatur ("He is a guest"). There is also a transliterated list of verb conjugations that only have the singular present forms. Some interesting examples are:

σαλουτατ, σαλουτας, σαλουτω (he salutes, you salute, I salute) τορκετ, τορκες, τορκεω (he tortures, you torture, he tortures) πλοουετ, πλοουεσ, πλοουω (he rains, you rain, I rain)

Here are some with the original Greek that include spelling mistakes in the transliteration:

γελᾷ, γελᾷς, γελῶ (ρειδιτ, ρειδεσ, ρειδω) γινώσκει, γινώσκεις, γιγνώσκω (νοουιτ, νοουις, νοουι) γεννᾶται, γεννᾶσαι, γεννῶμαι(νασκιτουρ, νασκαιρησ, νασκορ)

I don't see that these have any bearing on the principal parts, but list them in just in case and because the order of the persons shows variation in the traditions coming down to us.