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.
"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.
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.