in Hindi, they put a "." below the "da" to achieve what You are pointing to. but, I lol at "jaroor" "jindabad" when written in hinglish but, they speak as "zaroor,zindabad".. ie, they can imagine the word ja only not "za" for eg.
South Indians(except Tamil script) can understand the pronunciation issue because, "Zaroorat" is "Zaroorat" if written in South Indian languages not "Jaroorat"(with dot below ja). it is easy spotting native hindi/marathi(or other devnagari similar scripts) speakers because of the use of ja for za when writing in hinglish.
We say Gharib (poor), Khud (one's own self) etc
You probably say 'Garib' and 'kkhhud' as an Khana
..Also I've seen Indians confuse Sh and S as well: Sarab instead of Sharab
It dependes how much you are expert in producing sounds (means how many alphabets you practised as a CHILD). As a child if your 'vocal chord (a device responsible for producing sounds along with layrnx)' has practised these sounds then you can notice the difference between these sounds as an adult, otherwise like colorblindness ...a term I coined here Listening-muteness will you suffer from and for example a word berry (Bair in urdu/hind, but this word in Sindhi and Sariki will be variant in sound like puting a dot below 'B in Bair').
As for Sindhi and Seriki, they have even much big characterset of 56 alphabets...they have 5 alphabets unique to URDU (even there is B and a dot below B (say))...(J and a dot below J)...while the non native speaker(including urdu and Punjabi etc, I'm not aware about Hinko as I guess it has 56 as well). Sindhi (languagae of Sindh) and Seriki (Language of Multan and Bahawalpur : southern belt of Punjab)..
For example if a person claims that I'm Sindhi or Sariki speaking then they can be tested just by asking them to produce the 'Bair' and he will be kinda frustrated when you will tell you are not producing right word, but he would say , no it is B and native will tell that my vocal chord is producing a different sound than B but you feel it is B.......
I'm however amazed why a child vocal chord has the ability to learn every sound, but in later year he will loose the ability...
There are five unique additional sounds of Seriki and Sindhi which are absent in Urdu Characterstics. Even arabic and Persian charactsets are the subset of Urdu..from the discussion i feel as if hindi sounds characterset is also subset.....I guess the same is the case hindi has certain sounds missing, so the difference in the sound is misunderstood...
same is the case for Arabic people as they would say Pakistan as Bakistan...but as now as a kid they are learning english so now they can produce Pakitan....
As for my understand Sindhi and Seriki are the superset in characterset if we map all these to arabic characterset (script) then same happened where the sounds are similar then Sindhi and Seriki people put dot (in Seriki) over the character of arabic charcherstic and a 'toye' ط
in case of Sindhi...
Just as a side note:
I'd a bit researched as a part of studies about language alphabets ...