WONDERING: How can I develop the mathematical dialogic discourse ability of my children?

Below is the current data taken from a recoded maths session of my target group.

It's great to see the children explaining their thinking more freely however unfortunately they're not using the word 'because' often enough. They say things like "so you go 20.3 x 2 which is ...." but they don't explain why they multiplied 20.3 by 2 therefore, not justifying their thinking. It is also evident that the children are not asking questions of each other off their own bat.

So what can do or change to further develop their dialogic discourse? Although I've introduced the waka paddle prompts, had the children participate in talking activities and modelled dialogic discourse I'm not seeing the results I thought I'd see. This has me wondering do I just need to be more patient or do I have to try something different? Maybe it's a bit of both.

Recently, on my blog, I was challenged by Dr Jannie van Hees to look at incorporating real world maths into my class, to get my kids out of the class to explore the maths around our local environment. She suggested that using "

*... relevant, motivating, authentic contexts will generate much talk and figuring out....and when suggestions are shared, and justifications expected, rich maths and maths language dialogue will occur."*This makes sense to me I guess the challenge lies in incorporating it in my DMIC lessons but I'm sure it can be overcome.