'cant' has two historically separate sources. For the sense 'tilt/edge', 'cant' originates from Germanic (Old Norse/Old English) roots related to 'kant'/'kante' meaning 'edge' or 'corner'. For the sense 'song/talk/jargon', 'cant' originates ultimately from Latin 'cantare' ('to sing') via Romance (Old French/Anglo-French) usage, which gave rise to senses of 'song' and later 'sung or repeated formulaic speech' and 'jargon'.

The 'edge/tilt' sense: 'kant' (Old Norse/Germanic) → Middle English 'cant' (meaning corner, edge, oblique surface) → modern English 'cant' (tilt, bevel). The 'speech/jargon' sense: Latin 'cantare' ('to sing') → Old French/Anglo-French forms related to 'chant'/'cant' (song, chant) → English 'cant' used for sung or recited phrases and later extended to jargon and insincere moralizing speech (beggars' cant, cant as sanctimonious talk).

Initially there were distinct ideas: one meaning related to an 'edge' or 'corner' (leading to 'tilt' or 'bevel'), and another related to 'singing' or 'chant' (leading to repeated, formulaic utterances). Over time these evolved into the modern senses: physical tilt/angle and figurative senses of jargon or insincere, sanctimonious talk.