@Ajitha,
Your child’s chart shows afflictions to Lagna, Lagna lord, 2nd house, 2nd Lord and karaka for speech Mercury. The current dasa is also of the 8th lord which is also the nakshatra lord of the 6th house of roga.
All this is making speech difficult. Along with seeing specialist speech therapists, you can try the following:
1. Play the Vishnu Sahasranama daily so that the child hears it.
2. There is a seed called “Alale kayi” in Kannada language. It has to be rubbed on a thick sandalwood plate (the one used to make sandalwood paste). Mix a small amount of this paste with honey and let the child lick it daily in the morning. This has helped in some cases.
3. On a shravana nakshatra day, perform a honey abhisheka for Laxmi Hayagriva swamy if such a temple is accessible to you.
whenever any remedial measures are done make the proper sankalpa for the speech problem of the child.
Please remember these are earnest attempts. Result will be decided by the Lord above only.