Written Cantonese Pronunciation 2
Well, 俾 is BEI, and 给 is KAP in Cantonese pronunciation. In fact, 俾 and 给 also can be pronounced in Mandarin: 俾 is something like BI, I guess, and of course 给 is GEI.

So, they won't get confused, because they would certainly be taught that both words contain the same meaning but with a different pronunciation. In fact, I think 俾 is sort of like an unofficial word, which people usually use in texts/chats, and 给 is the official one. If you noticed, songs usually use 给 instead of 俾 :)