M.B.
My 16 month old just said Ma Ma for the 1st time a couple of weeks ago, before that it was only Da....Da....Da-Da...
We do work with ECI for other issues and they explained that if a baby/toddler is trying to learn something new, like walking for example, speech will G. right out the window until they learn that new task. Only one thing at a time is what they said to us.
Good Luck!!!