I have been told and seen what people say this means but would like to
know what the original words meaning were.

In english it could mean anything from talking babytalk or talking a
different language than the author did.

I know this is no doubt a stupid question but searching for this
answer has gotten very confusing.

Also how would you know you were hearing or speaking in tongues if you
understood what you were saying or hearing?

I would like a better understanding of these terms

Mr 16:17 And these signs shall follow them that believe; In my name
shall
they cast out devils; they shall speak with new tongues;



Matt