When and how did the letters E and I "swap", compared to other Romance languages?

Question

I'm trying to understand how some words / word stems / prefixes and suffixes have a "swapped" E and I compared to other Romance languages, or (Vulgar) Latin.

First, but not the only, is the accusative and dative personal pronouns.

For example, the accusative pronouns in Italian are mi, ti, ci, si, etc, whereas in French, they're me, te, ce, se, and except ce, they are also the same in Spanish, Portuguese, and also in (Vulgar) Latin. In the meantime, while me, te etc. do exist in Italian, their meaning is very well aligned with "i-counterparts" in other languages, for example Spanish mí, ti and French moi, toi. To some extent, I'd say me and mi is "swapped" in Italian.

Interestingly, the suffix version of these pronouns sometimes retain the -e form, for example dammelo instead of dammilo, but they're still -i in mangiarsi, vederti, etc. This seems to have a phonetic reason rather than an etymological reason.

Some other words, like se and si, also have swapped meaning in Italian and in other Romance languages. Italian se is equivalent to si in French and Spanish (means "if"), and vice versa (a pronoun). Note no accent in this paragraph because Italian sì = Spanish sí = French Oui.

Other examples of basic words or affixes include di (de in other languages, as well as Latin) and the ri- prefix (means to repeat, appears to be re- in other languages). (Latin doesn't use the word de the same way as nowadays, it has noun declension for the same usage.)

There are also individual words having this E/I swap in certain positions (mostly word-beginning, no matter whether stressed or not), e.g. finestra < L fenestra (FR fenêtre, ES fenestra), vetro < L vitrum (FR vitre, ES vidrio), vedere < L videre.

Google-ing for "Italian swapped E and I" gives no relevant result. Can anyone help clear my confusion?

Answer 1

It's a good question! I try to be fast, what you do not know about the "PERSONAL PRONOUNS" in the "funzione complemento": It's divided into two forms in Italian language:

The forma debole (weak form), also called atona (mi, ti, etc.).
They always lean on the verb, can previous it but can also follow it.
Ex. 1) Ci venga a trovare, Ragionier Pozzi!
Ex. 2) Verrà a trovarci, speriamo bene..

But there is also the forma forte (strong form), also called tonica, which are basically used after the verb, which are the same as the other Romance languages (me, te, etc.).
Ex. 1) Peggio per te, ah ah!
Ex. 2) Scegli me, ti prego.

The forte form takes on particular importance in the sentence, having an accent of its own.
The debole form, as the word says, has no prior accent.
This last form, also called "particella pronominale" and "pronome clitico" is used only for the complemento oggetto (which answers the question Chi? "Who?" for an individual and Che cosa? "What?" for an object) and complemento di termine (a chi? "to whom?", a che cosa? "to what?").

Ci venga a trovare
"Venga a trovare", Who? We (CI)

Ti consiglio di vedere questo film
Consiglio a chi? to whom? to you (TI)

In practice, with the Forte form, we want to emphasize the pronoun.
"Per quell'incarico hanno scelto me"
(the Forte form has an exclusive value to me: the speaker emphasizes that he was preferred to others).

If instead you want to have a purely informative tone, use the Debole form.
"Mi hanno scelto per quell'incarico."

You can find a nice table on the Italian wiki https://it.wikipedia.org/wiki/Pronome_personale_in_italiano

I hope I've been exhaustive.

Ciao!

===EDIT===

"De" is used in other Romance languages and from the mother language, Latin.
In Italian it actually changes:
Ex. 1) ita. discendere, lat. descendĕre
Ex. 2) ita disperare, lat. desperare
Even if the "de" is used in various Italian dialects / slangs
Ex. "È de Lorenzo" (std. È di Lorenzo).

"Se" (in Italian it means "if") I had never noticed that in other languages they have the meaning of "sì" ("yes"). Indeed, by doing a short research, in Latin there is much more this presence of E that in Italian.

We must consider that Italian (as well as other Romance languages) in the end is only one neo-Latin language, then each one has "evolved" on his way for too many conditions (invasions, trades, etc.) and probably sometimes without a real reason (maybe just because it sounds better).

=== EDIT x2 ===
Thinking about it, I confirm that the E in Italian is very present, almost as in other neo-Latin languages, only in dialects / slang.
Plausible examples:
Ex. 1 "Me ha detto che ce sei domani, vè?" (Mi hai detto che ci sei domani, vero?")
Ex. 2 "Se, e chi te l'ha detto?" (Sì, e chi te l'ha detto?)
Ex. 3 "Credi che menta?! te se vole troppo bene pe dirti 'na bugia". (Credi che menta? Ti vogliamo troppo bene per dirti una bugia).
If I'm not mistaken, this excessive use of the E remained in Rome and little more. Elsewhere it is seen too much as an ignorant parlance.

Answer 2

There is actually no “swap”. The indirect personal pronouns in Italian have two forms, strong and weak.

The strong form generally carries a tonic accent, whereas the weak form is always clitic.

For instance, the direct object can be either me or mi:

Hanno chiamato me / Hanno chiamato te / Hanno chiamato lui
Hanno chiamato noi / Hanno chiamato voi / Hanno chiamato loro

Mi hanno chiamato / Ti hanno chiamato / L'hanno chiamato
Ci hanno chiamato / Vi hanno chiamato / Li hanno chiamati

In all cases the pronoun is the direct object (complemento oggetto). The last one has “lo” with the usual apocope. Similarly for an indirect object (complemento di termine):

Faccio un regalo a me / Faccio un regalo a te / Faccio un regalo a lui
Faccio un regalo a noi / Faccio un regalo a voi / Faccio un regalo a loro

Mi faccio un regalo / Ti faccio un regalo / Gli faccio un regalo
Ci faccio un regalo / Vi faccio un regalo / Gli faccio un regalo

Only in the third person there's a trace of the Latin case system and for different complements different forms are used: lo is accusative, gli is dative, ne is genitive; si is for the reflexive form.

^{Current Italian uses gli also for the plural; purists would only allow Faccio un regalo a loro}

The sentences in the two examples mean essentially the same, with different emphasis.

The table below lists the forms (strong = forte, weak = debole)

The reason for the vowel alternation is most likely phonetic. This is confirmed by the fact that when more pronouns are used in clitic position, the form changes:

Dammi quel martello
Dammelo

Here is the table for the combined pronouns.

Consult “Pronomi personali” on the Treccani site for more information.

The forms mi and ti come from the datives mihi and tibi; me and te are the accusative forms. For the third person, lui, lei, lo and la come from Latin demonstratives; sé and si come from sui/sibi/se/se but are only used for the reflexive form in Italian.

The history of ci is another topic altogether; also vi is a bit strange.