The Nintendo Life gameplay video has a few sound effects in it.
We can hear Yooka jumping and Laylee panting while she attempts to fly: https://youtu.be/fY_otBmc6po?t=31s
More of Laylee 'flying' here, followed by Laylee running on top of Yooka: https://youtu.be/fY_otBmc6po?t=47s
I like how they sound. Chris Sutherland voiced both Yooka and Laylee, as well as Banjo and Kazooie.
I wonder what their mumbles will sound like.