The phrase 'cantar Gardel' is not a common slang phrase in the Spanish language. It might refer to 'singing like Gardel', referring to the famous tango singer Carlos Gardel, implying someone sings very well or is boasting about their abilities.
Examples
- Spanish: Juan se cree que puede cantar Gardel, pero realmente está fuera de tono.
- English: John believes he can sing like Gardel, but he is really off-key.