A few years ago, a Punjabi poet and acquaintance of mine, dismissed the term “Shahmukhi” as something that did not (or should not) exist. He has since anointed it the “Lahori” script, reasons of which I am not sure, other than that Punjabi may be written in the script in and around Lahore.
The term “Shahmukhi” means “from the mouth of the king (shah).” Which king is a matter of conjecture. One may surmise “Shahmukhi” sprang from the mouths of the Muslim rulers of the Punjab or from Ranjit Singh who maintained the use of Persian in his court and the use of its nastalliq script style, the style most commonly used for Shahmukhi.
Unlike the Gurmukhi and Devanagri scripts, Shahmukhi does not constitute a separate script. We can define Shahmukhi instead as the name given to the Perso-Arabic script when used to write Punjabi, including several letters for sounds found in Punjabi. The term itself is rather quaint and seems to have deliberately been coined so as to have Shahmukhi play partner to Gurmukhi.
But Shahmukhi exists; it has a name and has been naturalized into Punjabi. Those who consider Gurmukhi to “be” Punjabi do Punjabi a disservice. For Punjabi has not only the facility of Gurmukhi, but also the elegance of Devanagri and the beauty of Shahmukhi. From whose mouth then did the term spring? Perhaps not from a king, but from a Punjabi so let it spring some more!