Hi..
I don't want to panic you, but have you researched autism? That is one of the red flags of an autistic child is no language. My daughter is autistic and maybe you should look into it. There are different degrees of autism and just because she may seem "normal" we didn't figure it out in our daughter until she was 3 1/2 because she seemed to be pretty normal also. Its just a suggestion to look into. Here is something I found online for you....
Watch for the Red Flags of Autism
(The following red flags may indicate a child is at risk for atypical development, and is in need of an immediate evaluation.)
In clinical terms, there are a few “absolute indicators,” often referred to as “red flags,” that indicate that a child should be evaluated. For a parent, these are the “red flags” that your child should be screened to ensure that he/she is on the right developmental path. If your baby shows any of these signs, please ask your pediatrician or family practitioner for an immediate evaluation:
No big smiles or other warm, joyful expressions by six months or thereafter
No back-and-forth sharing of sounds, smiles, or other facial expressions by nine months or thereafter
No babbling by 12 months
No back-and-forth gestures, such as pointing, showing, reaching, or waving by 12 months
No words by 16 months
No two-word meaningful phrases (without imitating or repeating) by 24 months
Any loss of speech or babbling or social skills at any age
*This information has been provided by First Signs, Inc. ©2001-2005. Reprinted with permission. For more information about recognizing the early signs of developmental and behavioral disorders, please visit http://www.firstsigns.org or the Centers for Disease Control at www.cdc.gov/actearly.