In the horoscope of your daughter, there is Kaalsarp dosha. Kaalsarp dosha is formed when all the planets are on one side of the birth chart As she is born under Magha Nakshatra, there is gandmool dosha. Also Mercury which is the 3rd lord is in the 6th house with Saturn the planet of delays and obstacles. Mercury itself is retrograde and combust. Ketu aspects the 6th house. She will be a slow child due to the planetary positions. You should do astro remedies for her.
Your daughter is born in Cancer lagna. The lagna is aspected by Sun, she will not hear any words. She will act according to her own.
Her vocal chords are fine as 2nd cusp sub lord Venus and 2nd lord Sun are aspecting Taurus from a watery sign. So there would be delay in speech.
Now running period is Venus dasa Venus Bhukti upto 03-04-2023.There are chances for her to speek in July 2020, Dec 2020, Mar-April 2021.
In Jupiter antara i.e from 12-08-2021 she starts speek fully.
Note: As lagna lord Moon is in the sub of Saturn, delays and postponements would be there in her efforts. Success would be in the subsequent efforts only.
Hence you need not feel. She will definitely pick up by Aug 2021.
The lagna is aspected by Sun, “she will not hear any words”. should be read as she will relish others’ advice. She feels independent.
I advise you to take her to doctor and do as per their advice.