Dear Thomas,
Your concerns revolve around two areas: communication and social-emotional development.
It is clear that your daughter's development of speech and language is not what you would expect for her age. Seek an evaluation by a Speech/Language specialist, who can help pinpoint with some precision the areas in which your daughter is deficient, and develop a plan to address them.
On the social/emotional front, there are indicvations of problems, particularly in relation to the lack of reciprocal social relationships. However, I wouldn't assume yet a condition along the Pervasive Developmental Disorder spectrum. What is called for is a developmental evaluation, and be sure to include a child psychiatrist on the team. A developmental pediatrician and/or developmental psychologist should be on the team as well.
Her hearing has been tested. She was within the normal range. Although when they try to look in her ears, she covers them and screams.
Have you had her hearing tested?
I am a speech-language pathologist. There can be a wide range of behaviors for a child diagnosed with autism or PDD. I would definitely have your child evaluated by a speech therapist and by someone in the medical profession (pediatric neurologist possibly). Whatever the diagnosis is, your child's speech and language skills are not at the level they should be. I believe that therapy should begin as early as possible. Good luck