As per
Wikipedia: Thieves' cant (also known as thieves' argot, rogues' cant, or peddler's French)
1 is a cant, cryptolect, or argot which was formerly used by thieves, beggars, and hustlers of various kinds in Great Britain and to a lesser extent in other
English-speaking countries. It is now mostly obsolete and used in literature and fantasy role-playing, although individual terms continue to be used in the criminal subcultures of Britain and the United States.
It was commonly believed that cant developed from Romany. Etymological research now suggests a substantial correlation between Romany
words and cant, and equivalents, in many European languages. However, in England, Scotland, and Wales this does not apply. The Egyptians, as they were known, were a separate group from the standard vagabonds, and cant was fully developed within 50 years of their first arrival in England. Comparison of Romany
words in the Winchester Confessions taken in 1616 with modern Welsh Romani show
high commonality. This record also distinguished between Romany and Cant
words and again the attributions of the words to the different categories is consistent with later records.
Me personally, i think it means YEE HAW PARTNER
YEE HAVE YAWS
YEE LAST YAAAAA!!!!
Criminal
1: “Ho sir, you’re clearly a f'reign'
r. Wend readeth this cant so yond thee
may knoweth how to maketh wage 'round h're”
Wandering Beggar: “what?”
That is the Thieves' Cant