My baby inhaled cannabis smoke when she was 5 months old and now she is 4 and can't say a word or make eye contact. Could it be the cannabis effect?

No. She should be seen by a doctor to assess the reason for the developmental delays. A one time unfortunate exposure is not the likely cause. .
No. No, at least not the way the question is phrased. If your baby used cannabis regularly there maybe some causation, but if we are talking about one incident of inhaling a small amount of cannabis smoke second hand, this would not cause significant permanent damage.