I am unsure as to which of these seems more formal.
My parents will reside with me and my family.
or
My parents will reside with my family and I.
Or is there a better (formal) alternative to it?
I am unsure as to which of these seems more formal.
My parents will reside with me and my family.
or
My parents will reside with my family and I.
Or is there a better (formal) alternative to it?
My parents will reside with me and my family.
This sentence is okay, because if we shorten it, leaving only me and omitting "my familiy", we notice nothing strange:
My parents will reside with me.
Because this pronoun is not in subject position, it's okay to use the form me. The pronoun is the object of the preposition with. Such pronouns are called object pronouns.
Your second sentence is actually considered ungrammatical (but look below for a fuller view):
My parents will reside with my family and I.
Why? Because I is a subject pronoun, and should not be used in object position. Let's see how the sentence will look if we omit "my family":
My parents will reside with I.
This is a strange-sounding sentence.
In "standard" English there's a tradition to frown upon the use of me in subject position. Why? Because when we omit the "and-part", we get this:
Me will reside with my parents.
Sounds a bit strange. The "correct" form of the pronoun for subject position is I.
P.S. When someone attempts to use I instead of me in object position in order to be more "formal", it is called "hypercorrection". Quoting Wikipedia,
Jack Lynch, assistant professor of English at Rutgers University, says that correction of "me and you" to "you and I" as subject leads people to "internalize the rule that 'you and I' is somehow more proper, and they end up using it in places where they shouldn't – such as 'he gave it to you and I' when it should be 'he gave it to you and me.'"[7]
On the other hand, the linguists Rodney Huddleston and Geoffrey K. Pullum claim that utterances such as "They invited Sandy and I" are "heard constantly in the conversation of people whose status as speakers of Standard English is clear"; and that "Those who condemn it simply assume that the case of a pronoun in a coordination must be the same as when it stands alone. Actual usage is in conflict with this assumption."[8]
That's a nice observation by H&P. My test with leaving out "my family" and dissolving the coordination is invalid, from this point of view.
So let's say that's basically how the awkwardness of I in object position and of me is subject position is usually explained. Linguists are arguing about whether it is really ungrammatical. "The jury is still out", as they say.
The take-home message is that your sentence 2 will be marked off as erroneous if you take an English language test.
Related posts:
Is it "Tom and I" or "Tom and me" in "Keep Tom and I/me updated"? -- the deepest answer is in this post by F.E.. A definitive answer, I might say.
Can ME be a subject? - a nice answer by Snailboat to a related question.
Between you and me - or Between you and I - on ELU SE.
“My friends and I” vs. “My friends and me” vs. “Me and my friends” - on ELU SE - with a great psychological explanation of why we tend to use me in coordination.
Instead of trying to judge which alternative is more formal (which is already addressed in other answers) between:
a) My parents will reside with me and my family.
b) My parents will reside with my family and I.
I'd like to offer an alternative that I believe is a better choice if you want to keep the tone formal, and want to avoid the issue of me and X vs. X and I at the same time:
My parents will reside with me, and with my family.
Some other possible alternatives I think possible are: My parents will reside with me, along with my family (admittedly, this could be a bit ambiguous, but all interpretations would end up that everyone stays together anyway), My parents will reside with myself and my family (this could be a bit risky, but I believe that it would fit your context well enough).
People like me and my friends don't like people who use my family and I as the Object of a verb, especially in formal writing.
This isn't because it is ungrammatical, it's because we believe that most of the people who say things like that never actually speak like that when they aren't trying to sound posh. We also think that they are making a grammatical mistake because they are trying to sound posh. We don't believe that posh is necessarily a good thing to aspire to - especially if you get it wrong.
However, there is no doubt that for some speakers my family and I is genuinely grammatical. Co-ordination in English is well known for blocking case. What this means is that when we join a pronoun with another noun phrase in English, using a word like and or or, the pronoun doesn't have to be in the same case that it would be on its own.
So for example:
... is ungrammatical, but:
... is grammatical (even if people like me don't like it).
Similarly:
... is ungrammatical, but:
... is fine (even if people who want to sound posh don't like it).
Generally speaking, using a nominative pronoun in a coordination is often perceived as formal, even when that coordination is an Object of the verb. However, when it is the Object of a verb, some people may also think that you are badly educated if you use a nominative pronoun.
Using an accusative pronoun in a co-ordination functioning as Subject can often sound informal.
If you want to sound as if you have good formal English, my advice would be not to use nominative pronouns (I etc) when the phrase is part of an Object.
There is no doubt that the statement that seems more formal is
My parents will reside with my family and I.
And if you want to sound more formal, you can use that sentence.
Just note that it is possible to argue that it is technically not grammatical, as CopperKettle has done. But this is by splitting the dual phrase into component parts. This actually does not necessarily prove anything.
See this comprehensive answer by F.E. regarding the similar construction Tom and I as coordinated objects.
As pointed out by the passage referenced in CopperKettle's answer, many native speakers will use this form in the exact context of wanting to sound more formal. Therefore, since many native speakers will say such a thing, can we really say it is ungrammatical?
This takes a descriptive linguistics approach (observing what people actually say) over a prescriptive linguistics approach (determining what other people should say).
This difference is especially acute when it comes to pronouns. Modern English has only the remnants of a case system. So claiming that one cannot use my family and I as the dual object of a preposition is just as prescriptive as saying that one should not say It's me. But we say It's me all the time and we say with my family and I all the time.
Grammatically, I think that there is a few possible answers independent of formality, "My parents will reside with my family and me", "My parents will reside with our family", or simply "My parents will reside with us."