Sobbasi in other word "Dhakaiya Sobbasi Language" that is "Dhakaiya Sobbasi Jaban" in fact is a dialect of Urdu Language called "Dhakaiya Urdu"
Two pioneer public groups "Dhakaiya Sobbasi Jaban" and "Dhakaiya Movement", created by Nazir Uddin, are consistently writing this Sobbasi language using Bangla Script; and promoting to preserve it.
There are two youtube channels as named "Dhakaiya Movement" and "Dhakaiya Sobbasi Jaban" created for practising Sobbasi.
Dhaka Shahora Urdu Songskrti [ Urdu Culture in Dhaka City] ISBN 984-8319-38-7, published on February 2006 and authored by Rafiqul Islam Rafiq ,provides historical evidences on this regard.