Mystical (Silent) Prayers

https://churchmotherofgod.org/articles/reasons-for-secret-liturgical-prayers/?highlight=secret   

 https://www.orthodoxwitness.org/inaudible-prayers-should-be-read-out-loud/   

 https://www.amazon.com/Heavenly-Banquet-Understanding-Divine-Liturgy/dp/B0FDKHW7T8 

 https://books.google.com/books?id=HSohBgAAQBAJ&lpg=PA232&ots=aU2SsY9JOA&dq=inaudible%20prayer%20orthodox&pg=PA228&fbclid=IwAR32kE3k9a2ykH78vUMYvGxzPE3DzChZbMfLG9Df_UXi_tzBzugvUjQbE7w#v=onepage&q=inaudible%20prayer%20orthodox&f=false