English is not my mother tonge and I had this argument with a friend the other day. I think that putting the "too" after the subject instead of at the end of the sentence is not correct but he disagrees. Can anybody help me? Thanks a lot!
The main difference is the emphasis. The normal, which is to say un-emphasized, phrasing is "He wanted to do it too." However, one of the ways in which subtle shades of meaning are obtained in English is by varying word order, causing the word(s) moved to be emphasized.
A classic example is the retort attributed to Winston Churchill's after an editor criticized his word order: "This is nonsense up with which I shall not put!"
The "too" would need to be isolated by commas to be correct. But commas also represent a pause in speech and sometimes that is the only reason they are used in a sentence. Given that people naturally tend to pause at commas, the "too" on the end gets rid of that longer, more awkward sentence with the pauses. Though both would be understood and neither is "wrong" to any prosecutable degree, I'd stick with the "too" at the end for fluency.
Generally speaking, people don't use enough commas. Or perhaps it is that they don't use them where they are needed. If you read a sentence aloud and put a comma where there would be a natural pause, you should be all right. But far too many people omit the commas and then the meaning of the sentence is obscured. When they read the sentence to themselves, it seems fine. But they forget to realize that the reader may not put the emphasis in the same places without commas for guidance. That is a failed responsibility of the speaker (or writer).