How can I get them to actually listen to me and pay me some respect?

OK so this is more about my mother and grandmother but my older brother a little bit. I dont know if I've askjed about this before but I really like some more help now. Well whenever I'm talking about something, explaining something telling them something or whatever my mother and grandmother will start talking in amongest themselves about garden steps or something stupid like that. It's like a heap of soil matters more then what I've got to say doesnt matter at all and I dont deserve the respect to be listened to for thirty seconds. It really hurts my feelings and about six weeks ago I got so annoyed by it I banged my gl on the table top and told them I didnt know why anyone bothered trying to communicate with them. I got grounded for a fortnight for being "disrespectful" but theyre the ones that are being disrespectful, talking to them wont help because oh surprise surprise theyll start a conversation in amongest themselves. What do I do? This is going way too far!!!!