Sure they are common in modern English. (I only speak that version, being modern myself ;) [1]
>Is what you're talking about a bit different? Can you dive in a bit?
Sure I can. Thanks for asking.
Yes, I was talking about something different. But I seem to have been misunderstood by a few people in this subthread.
No worries, it happens. Human languages are not perfect, nor are they always unambiguous. Nor are humans perfect, in writing or interpretation. :)
I wrote the comment casually, so did not think to check how it might be understood differently by others.
When I said
>many such short forms come from or are unique to Indian English.
, I meant, first of all, just "some", because "many" does not necessarily mean "most", let alone "all". It just means "many", for some value of "many". It does not necessarily imply a comparison or relative valuation, such as, "many" relative to the total number of acronyms.
(5000 is a big number on its own, but not compared to 5 million.)
And secondly, I had first come across usage such as gf and bf in emails between Westerners and Indians known to me, some 15-odd years ago, and Indian (techie) English has many :) possibly unique acronyms such as o/p for output, i/p for input, so I thought at the time, that gf and bf might be Indian English acronyms, having not come across them in general Western English usage, at least before that.
[1] An arcane reference to an Asterix comic issue, maybe Asterix in Rome (or Italy), where they talk about learning modern languages such as Latin :)