"I touch it too."
Many English speakers are guilty of imprecise English. (I am a big offender.) We write the way we speak, and when we say the sentence "I touch it too." , if it isn't already obvious from context, we convey our meaning with the word we stress. If we stress either "I" or "too", it conveys the meaning others are touching it too. However, if we say "I touch IT too" with emphasis on "IT" , the implication is that I am touching more than one thing, a totally different meaning from the same written sentence. In Korean, it is clear that more than one person is involved, though the meaning can not truly be determined without more context. In English, we can't even tell if it is multiple actors or multiple objects.
There actually should be something in the sentence indicating what is being touched. "It" is definitely not implied, as , without context, there are a number of possible translations. He / she touches me too. You / they touch me too. I also touch her / him. There is even a problem with the proposed translation ,as it gives the impression I touch more than one thing, when actually it means I am not the only one to touch whatever it is.
Yes, that would work, but then that would translate to "I touch it". In order for it to translate to "I touch it too", it should be "나도 그것을 만져요" the -다 ending is just another honorific as the -요. If you want to know more, I would suggest that you find the difference between the two honorifics.