When the phrase is used as an object, why so many native speakers are saying "you and I" instead of "you and me"? I'm not a native speaker but I thought "you and me" is correct. Not sure if this falls into the same category, but "Just between you and me" sounds more natural than "Just between you and I".
This is an example of hypercorrection, which is when native speakers make an accidental error in their zeal to avoid a different error.
In this case, the error that's being avoided is the error of writing "you and me" in subject position, as in the following sentence:
You and me are going to the store.
This is formally incorrect, although it's very common in contemporary spoken English. Because they have been taught that this is incorrect, many people hypercorrect and change "you and me" to "you and I" in all positions. That is, they incorrectly learn the rule about when to use "you and I", and so produce sentences like the following:
You and I are going to the store. [Correct]
He'll come to the store with you and I. [Incorrect]
"You and I" is the subject. "You and me" is the object.
"You and I hate Phil." "Phil hates you and me." "Phil is hated by you and me." All of these are grammatically correct. (No offence to Phil.)
It really winds me up when people hypercorrect because they think that "you and me" is always wrong. "Phil hates you and I." NO! This is worrying.
The best way to work out if you should be using "you and I" or "you and me" is to take away the "you and" and see if the sentence sounds right with just I or me.
"I hate Phil." Sounds good. "Me hate Phil." Sounds like a caveman talking!
"Phil hates me." Sounds good. "Phil hates I." Sounds ridiculous!
They are synonymous but grammatically different. They are often used interchangeably (incorrectly) by native speakers. There is a simple way to tell which one to use, by imagining the clause without the "you and" part:
Example: You and (I/me?) should spend more time together
Imagine: "Me should..." (this is clearly wrong)
Imagine: "I should..." (correct!)
Answer: You and I should spend more time together
Example: He should have spoken to you and (I/me?).
Imagine: "He should have spoken to me" (correct!)
Imagine: "He should have spoken to I" (wrong)
Answer: He should have spoken to you and me.
An alternative view is that "you and me" was always OK until somebody decided in the 18th century that English should be like Latin and started teaching that you have to use 'I' when you would use 'ego' in Latin. Since the rule taught since then is hard for English speakers to grasp (since grammatical case is marginal in English), many people are unsure of where to apply it, hence the hypercorrection. In fact, in Joseph Emonds' 1985 paper "A grammatically deviant prestige construction" he shows that there are slightly more complicated examples (which I cannot recall to mind) where even people who think they do know the rule are often unsure. His paper argues that English with that rule is not a possible natural language, in the sense that there is not enough information about case available to an English-speaking child to construct the rule. His claim is that the rule exists only as a rule learnt in school or equivalent.
There are three styles of using "you and I" or "you and me". For each I will give two example sentences - the first with "you and I/me" as the subject and the second with "you and I/me" as the object.
Style 1: You and me beat him. He hates you and me.
This is normal English as learned by many children, found in prose and dialogue in works of the best authors, and taught to learners of English as a second language. I is of course the normal subject pronoun and me is the normal object pronoun. But in this style, me is also an emphatic variant of I that is used (among other uses) whenever several nouns or pronouns are joined into a single subject or object. This is the most correct style in the sense that it is how educated normal people normally speak.
I guess that some French influence was at work in the formation of this grammatical phenomenon, since alternation between French je (I) and moi (me) follows very similar patterns.
Style 2: You and I are reading the book. He is attending the course along with you and me.
This is formal, high-prestige English as taught to native English speakers who want to improve their language to advance in society. It is the most correct style in the sense that it has the highest prestige. But it is not how people normally speak, and most children even in educated families do not learn this style naturally.
This style is similar to how other Germanic languages work naturally, and very different from French.
Style 3: You and I should go to the party. She wants to meet you and I.
This is the hypercorrection that logically results when someone is taught style 2 but doesn't really understand it beyond "'you and me' is sometimes (hypercorrected to: always) wrong". As much as I hate to admit the fact, this style is so common that it is arguably correct. We can even justify this by arguing that in style 1, the case information gets lost when two subjects or objects are joined, and then using subject case is pretty logical unless we specifically want the emphatic variant to emphasise the first person.
This pattern is unlike any other language I know, at least among those that distinguish subject and object case for pronouns. In particular, it doesn't exist in French because French speakers are not taught to think of their version of style 1 as wrong, and it doesn't exist in German because style 1 is just plain wrong in German and every native German speaker grows up with style 2. (So both French speakers and German speakers have no reason for this type of hypercorrection.)
To add to the previous examples by kdt.
The pronoun "I" is in the subjective case whereas the pronoun "Me" is in the objective case. So when you want to tell that you did some action then use "I"
e.g. My mother and I went to the market.
If some action is received by you then make the use of "Me".
e.g. Vijay offered some chocolates to you and me.
The correct phrasing is "between you and me". This brief article does a great job of explaining why.
In standard English, it’s grammatically correct to say ‘between you and me’ and incorrect to say ‘between you and I’. The reason for this is that a preposition such as between should be followed by an objective pronoun (such as me, him, her, and us) rather than a subjective pronoun (such as I, he, she, and we). Saying ‘between you and I’ is grammatically equivalent to saying ‘between him and she’, or ‘between we’, which are both clearly wrong.
People make this mistake because they know it’s not correct to say, for example, ‘John and me went to the shops’. They know that the correct sentence would be ‘John and I went to the shops’. But they then mistakenly assume that the words ‘and me’ should be replaced by ‘and I’ in all cases.
It depends from the context. As a way to check what is correct, remove you from the sentence, and see if it's correct.
You and I will go to the cinema.
That is correct, as I will go to the cinema is correct.
Laura will come to the cinema with you and me.
That is correct, as Laura will come to the cinema with me is correct.
As a general rule, I is used as subject, and me as object.
I have a feeling that a good many teachers of English grammar did a disservice to their students years ago when they taught their students to say, for example,
My girlfriend and I are going to a party on Friday night.
A teacher would then say, "Always put yourself second, which is not only correct but is also the polite thing to do. Put the other person first, and then yourself." I say, so far so good.
What the teacher neglected to say, however, is that the "wife and I" construction is correct only when it's being used in the nominative case, when both "girlfriend" and "I" are the subjects of the sentence. It is not correct, however, when the "wife and I" are no longer in the nominative case but in the objective case, as in the sentence below:
Dick and Jane are taking my girlfriend and me to the party on Friday night.
In this sentence the "I" is being taken by Dick and Jane. "I" (and the girlfriend) is the object of their taking, and Dick and Jane are the subjects who are doing the taking. You wouldn't say "Dick and Jane are taking I to the party," would you? No, you'd say they are "taking me."
Sure, putting yourself--I--last in a list of people, whether 2 or 200, is correct and polite, but only if all the people together comprise the subjects of the sentence, not the objects. If you and they are subjects, put yourself last using the nominative I. If on the other hand you and they are objects, then put yourself last using the objective me.
A few examples:
The marriage counselor gave my wife and me some good advice.
My wife and I were benefitted greatly by seeing a marriage counselor.
Would you like to go hiking with Rachel and me?
Rachel and I would like to go hiking with you, if you'd like.
Now be sure to keep this information just between you and me.
You're right when you say that I should be used in the nominative and me in English's oblique or objective case, usually as an object of the verb phrase, but also of a prepositional phrase. A case where you and I is incorrect is when the pronoun is the object of the the preposition between.
"Just between you and me".
*"Just between you and I".
"The table is between the couch and him."
*"The table is between the couch and he."
All normal rules regarding the nominative are superseded here by the preposition. People using you and I in this case, after an oblique preposition, are overgeneralizing the rule that you ought to say it instead of you and me.
In standard English only between you and me is acceptable; between is a preposition and takes the objective case (us, me, him, her, them). None the less, between you and I is not uncommon in non-standard varieties of English. In particular, it might be entirely appropriate in dialogue, depending on the characters using it.
Shamelessly taken from Grammar Girl after a very short Google search:
Between is a preposition, just as on, above, over, and of are prepositions. Because prepositions usually either describe a relationship, or show possession, they don’t act alone; they often answer questions like Where? and When? For example, if I said, “Keep that secret between you and me,” between describes where the secret is to be kept. If I said, “I'll tell you the secret on July 5,” on describes when the secret will be revealed.
So, instead of acting alone, prepositions are part of prepositional phrases. In those example sentences, between you and me and on July 5 are prepositional phrases. And it's just a rule that pronouns following prepositions in those phrases are always in the objective case (1). When you're using the objective case, the correct pronoun is me, so the correct prepositional phrase is between you and me.
The simplest way of dealing with this (I find) is to remove the second object (in this case Mary) and then rework the sentence atound a single object (in this a disputed first person singular pronoun) and check which works and substitue that into your original sentence. If that method doesn't work, perhaps becuase it sounds clumsy, then just reword then the sentence to isolate the first person singular, then check and substitute.
Following that method, I started by adding a little more syntactical structure:
I've forgotten everything about the deal which was struck between Mary and me/I.
The addition here does not alter the meaning or grammar, or affect of the word between but gives us structure to do this:
I've forgotten everything about the deal which was struck including me/I.
Testing this, obviously I doesn't work, so, yes me is correct.
You can check this by exchanging Mary for me/I in the example:
I've forgotten everything about the deal between me/I and Mary.
Again, me is the only pronoun which fits.
I just thought I'd post a different view, since I don't see it represented here in any of the previous answers.
Huddleston and Pullum's Cambridge Grammar of the English Language (2002) rejects the description of "...and I" as a hypercorrection. You can see a bit more information about this in F.E.'s answer to a related question ("Between you and (“me” or “I”)?") but of course it's best to look at the book itself if you can get your hands on it.
Of course, from a prescriptivist standpoint, "between you and I" is clearly considered incorrect: this is separate from the matter of whether it is accurate to describe it as a "hypercorrection".
I think there is an influence of Jamaican philosophy in using I instead of me. From Wikipedia Iyaric:
I replaces "me", which is much more commonly used in Jamaican English than in the more conventional forms. Me is felt to turn the person into an object whereas I emphasises the subjectivity of an individual.
I is important in the normally objective phrase and therefore the subconscious feels that using I expresses the correct meaning.