"I only teach you" vs. "I teach only you" vs. "I teach you only"

Question

• I only teach you.
• I teach only you.
• I teach you only.

I think that all the sentences have same meaning, but my teacher says that they are different from each other.

I think that the expressions are different but their meaning are same.

Can you help me understand the meaning of each sentence?

Answer 1

Only is one of the words (like even, too, and also) that have a stressed focus word in the sentence.

The focus word takes a heavy contrastive stress in speech, no matter where only occurs.

• She only talked to Mrs. McGrew about Bill. (not talking about anybody else)
• She only talked to Mrs. McGrew about Bill. (not talking to anybody else)
• She only talked to Mrs. McGrew about Bill. (no activity except talking)

In these sentences, only appears before the verb phrase, which contains the focus in each case.
It can also appear right before the focus word (or right after, if the focus is a noun).

• She talked to Mrs. McGrew only about Bill.
• She talked only to Mrs. McGrew about Bill.
• She talked to Mrs. McGrew about Bill only.
• She talked about Bill to Mrs. McGrew only. (this works better at the end of a sentence)

Of course, in writing, there is no stress, so it's harder to tell what the focus is.
So in writing it's safest to put only right before the focus word (the word with contrastive stress)

This rule is discussed here, with references and examples.

Answer 2

The sentences do have different meanings. See the following EXAMPLES. (These are only examples of how the sentences can be interpreted but it depends completely on context, for instance, when, where, who is speaking, and to whom they are spoken.)

I only teach you. (meaning merely)

Can be taken to mean: I am merely your teacher. You must strive to understand what I teach. Or You must take what I teach and use it. Or I cannot take credit because I am merely (only) the teacher.

I teach only you.

This usually means I have no other students. Or You are the only student who understands. But this second possibility is not normal for this sentence. I mention it because when said that way, the teacher would continue on with more information.

I teach you only.

This sentence seems incomplete or is phrased by a non-native English speaker. I would normally expect to see this sentence continued with something like: I teach you only what I know, or I teach you only what you can understand. These express a limit to the scope of the teaching, instead of limiting how many are taught. Also: I teach you only until you go home. Or I teach you only enough to help you pass the test. As you can see, each of these limit the material taught.

If the last sentence were spoken by a non-native English speaker, it could mean any one of the above possibilities, because non-native speakers tend to change the location of words within a sentence to match how they speak their first language. In that case the student should seek clarification from the speaker. I would be inclined to think the speaker means to use it in the first context since it was not followed by limits, and there was no mention of other students.

So, to recap with EXAMPLES:

1. I only teach you. means I am merely the teacher.
2. I teach only you. means I have no other students.
3. I teach you only. means There are limits to what I teach you.

I hope this helps clear up some confusion.

Answer 3

• I only teach you.
• I teach only you.
• I teach you only.

These sentences all say essentially the same thing, you are only teaching one person. However, the way the sentences are arranged may change the emphasis slightly.

I only teach you.

Only modifies the subject I; one can say that the sentence means, I alone teach you.

I teach only you.

*Only modifies teach; one can be said I teach no-one but you. (nothing rlse is done.

I teach you only. Only modifies you. One can say, I teach you only you, no one else, but I do other things.

This is the most I can differentiate these, I hope a linguist comes along and sees more!