I grew up with po and opo (Tagalog common expressions of respect for one’s elders) words around me. And I still use them whenever I speak to elders. It’s not that I’m reminding them of their age, but it’s just a way respecting them.
My daughter is primarily taught of English words at home but I somehow manage to introduce Tagalog words which I think is essential for her to know especially when she goes back home with me. Like po and opo. Whenever she calls me Mama, I often response by answering “po” to her.
Since there are no words like these in English, we just stress the words “please” and “thank you” whenever needed. I’m proud to say that she’s slowly picking it up. She would sometimes say “pish” (that’s her baby talk of please) when she thinks she couldn’t easily get what she wanted.
Sometimes, she butts in when I’m on the phone with her Dada. I hold the line and tell her “wait please Deye“. After the conversation, I tell her not to butt in when mama is talking to someone.
I know it’s too early for her to understand these things. The earlier, the better.
After each conversation with any of the above words used, I say “good girl“.
I think it’s a good start on how to teach your child a polite conversation.