Oh, I’m monolingual but I know a bit about this one! :D
So, in a lot of languages, there are multiple verbs that mean, “to love,” which are each situational, while, in English, we derive the meaning through context
Like, “Te quiero,” refers to love for friends and family, aka platonic love, while , “Te amo,” or, “Ai shiteru,” in Japanese, is so achingly tender and romantic that you might as well write the other person a receipt for your heart, because it’s theirs now
At some point, English did have multiple verbs for, “to love,” but eventually English speakers decided, “to hell with it, I only want 1 broad term for these big mushy feelings,” because we hate having multiple words for things almost as much as we hate punctuation
TL;DR: cultures that are non-English speaking do tell their kids they love them, they just have multiple words that mean, “To love,” and English is the odd man out because it got tired of that and went