You two talking in another language and laughing won't exactly put your new office-mate at ease, you know?
...Dutch is the local language. We just talk English to make our other colleagues (we have several from other countries) at ease.
As for not wanting to shake hands... Well, it's not a custom or tradition that I'm familiar with... But overall pretty harmless. I do want to point out that there is no need to "respect" the things about other people that make no sense to you. Simply tolerate and deal with them. That would be my approach, at any rate.
It's not the hand-shaking that really took me by surprise. I had a good thought about it, and the thing that startled me most is that I needed to readjust my view AT ALL. I always regarded myself as a liberal-minded person who's OK with a lot of things, and still I had to get used to this. This makes me change my self-image more than my image of others (colleagues included).