In his introduction scene - he tells someone in his office - to correct their grammar and not to forget they work for a hindi newspaper.
Also consistently they have shown him have knowledge of - the hindi not so often used equivalent for an english word. Its these subtleties that take this show to another level.
He's used some hindi terms for correspondence studies, scholarship, awkward, etc to translate for Imli, Meethi :)
Also his appreciation for the poem Imli wrote for his wedding card with Malini, the garam tawa poem, what he tells Imli about kaala akshar bainz barabar... I've enjoyed all those references.
Shows Adi to be one - who does not think - usage of the hindi language vs lets see English makes anyone less... and thereby helps us believe that his connection with Imli is not hampered by their dialect or English pronunciation differences.
I remember Imli telling Malini's cousin also during Malini wedding that - speaking in English does not make anyone great...another Hindi vs English language reference in this show.