This phrase literally translates to 'one must read the card'. It's a Spanish slang term often used to mean 'to lay down the law' or 'to read someone the riot act'. It refers to the act of reprimanding someone or setting them straight about something.
Examples
- Spanish: Mi hijo llegó muy tarde anoche, así que tuve que leerle la cartilla.
- English: My son came home very late last night, so I had to lay down the law.