Teaching cantonese

I have always wanted to get my children to learn their 'father tongue': Cantonese. Haven't been successful - in fact, a total failure. Well, I can blame many things, such as the school focus being only English and mandarin, my wife is hokkien, the low economic value of cantonese ... . But if I am to be honest, I don't have to look very far. The root cause is traceable to me. As always, without the parent modelling it [my default language is english], it is hard to expect the children to pick it up seriously. To be honest, I don't have a foolproof argument for why i think the children should learn cantonese. I just think that it helps to know another language, and the natural choice - among many vying candidates such as Japanese, Spanish ... - is the one that reflects our ethnic roots best. That knowing cantonese helps them communicate better with their grandparents (and even less incentivizing, makes them feel at home in Hong Kong and Chinatowns all over the world) is extra motivation. Well, I received an encouragement a few days ago. My eldest son - who is doing his 'A' level now - said that one of his resolutions while awaiting the call for military service is to learn cantonese! That gave me a boost to try harder. As always, it seems sensible to start with the one that offers the least resistance: the youngest 5-year old. For the last few days, I have been working on him; I taught him some stock cantonese phrases like sek fai ti, guai guai ... He has been lapping them up. I hope this will last ...