Adding to what airelibre said, yes it is contracted, and should be in a more correct and formal speech (on daily speech we say ha-yeladot). It is because the "ye" is actually schwa or "zero vowel". It's hard to pronounce when saying ילדות so it is pronounced "yeladot", but when ה is added the schwa sounds like zero vowel again.
Why is it "the girls are speaking Hebrew" and not " the girls SPEAK hebrew"? Is there a diffrence?
Is it the same difference in definition (aka not much to difference in settings) in Hebrew for speaking & talking, discussing, telling etc...? Or is it like דרך, where even though there are literal differences in English, we really don't use them in non-necessary settings (I.e. Not governmental, engineering, city planning, etc)... You can call my court a street, and when I moved to a road I still call it a street. (The only reason I know they are not streets is because they are named XXX Court & ZZZ Road).