Talk down to – Phrasal Verb

Talk down to somebody

To speak to (someone) in a simple way, as if they cannot understand things as well as you can. [Falar com (alguém) de uma maneira simples, como se eles não pudessem entender as coisas tão bem quanto você]

Ex.: Our history teacher never talks down to us. [Nosso professor de história nunca nos passa a matéria de maneira simples]

Fonte: Cambridge Dictionary of American English.