ok quick rundown, MDMA is an amphetimine, so is speed, this is the first area of confusion. But they have very different effects. Some stuff that is sold as E has MDMA and/or speed in it (or who knows what else).
Methinks that either whoever told you about these is telling you that it is an E with very "speedy" feel to it (entirely subjective) or else its just a speed pill (contains only amphetimine with no MDXX product at all).
Either way tthe only method of telling for sure is to test it. Get yourself an E-Z test kit and if the liquid goes orange its just speed, but if it goes black/purple well then, you've got yourself some MDXX and happy rolling. Any other questions then first read the FAQ/Intro forum...