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?