She sounds a lot like my DD - very advanced in some areas but delayed in speech. She babbled and cooed as an infant, started saying "ma ma" and "da da" fairly early on, and then... stopped. (Both my kids did this, actually). Not another word until she was 24 months. Instead she'd stare into your eyes and point to whatever she wanted (we never taught her how to sign).
She had a proper hearing test done and passed it. She was sent to a speech pathologist who taught us the "Hanen, It Takes Two to Talk" instructional method, and voila: success.
http://www.hanen.org/hanen-programs/programs-for-parents/it-takes-two-to-talk-parent-program.aspxI believe it worked for DD(now 9) because I really think her speech delay was due to perfectionism. As soon as I silenced my constant stream of verbalizing and adopted the Hanen "child-led" approach which involves speaking one word at a time about whatever the child is focusing on, DD started speaking. She quickly made up for lost time and went from nothing to complete sentences in several weeks
