My son 2yrs old will be 3 in sept & is still not using complete sentences?

Complete sentences?? I expect 4-6 word phrases, more articulate word formation and interest in talking but full sentences would be a bit much. If you are concerned, contact the school district where you live. There is a nationwide child find program operated from the public schools that screens 3 yr and older kids for speech & language issues.

This may be a sign of developmental delay. Recommendation take your son to the pediatrician for evaluation of his speech development.