GeorgeX, I worked about 40 years in a variety of organizations, with a spectrum of personalities, before I retired. I performed several times as the young colleague, and also as the experienced old one. You have my sympathy.

A young colleague's excessively clear understanding of his or her importance can be thoroughly annoying. It's important to bring it up with your boss and with the team at the your first opportunities. Talking it over with others will generate information for you and your coworkers. This will give all of you an opportunity to improve your approach.

The age differential and the cultural legacy of different nations may generate some friction, though coping with these will strengthen you, the young colleague and the team. Some people have personality quirks they may not intend or even have awareness of that introduce frictions, too. Keep in mind that frictions are part of the social experience of working in groups of humans. It's easy to diagnose the problem incorrectly as caused by these conditions. You must cope with these things in collaboration. But, if that's all you have, then you haven't figured out the trouble yet.

I suspect the true difficulty arises from inadequately understood agreements among the parties. Again, it's part of working in groups, but even employees who must do what the boss says will be more productive if they discuss and agree on overall situation, on strategy, on procedure, on methods, and task by task, whenever practical. There are more-or-less coercive conditions that give a person authority to command others. But well-understood, willing agreements can diminish the value of command authority and enable greater enthusiasm and productivity.

I suggest you take an approach something along these lines...

Start talking. You can't do this by email. Talk and listen. Don't wait to get all your facts straight. Be honest and courageous enough to be wrong about some of it.

First, talk with your boss. Describe your concerns. Say you want to discuss it with all the team within the next week. If you have a daily scrum, that's an ideal time. Be concerned to treat the young one well, and tell your boss that is your intention. Listen carefully to what your boss says.

If a meeting in the next few days isn't possible, gather those of your team that you can to discuss the matter.

When you meet with the young colleague, be courteous and kind and completely straightforward. Let him know candidly that you value his expertise and accomplishments. Tell him you are having trouble working with him. Tell him you need a better agreement with him and the team regarding how you work together. Shut up to give him a chance to respond while you listen carefully.

What happens next depends on your circumstances. Be always courteous and honest. Seek agreement.

Some optional reading you may find helpful: All these are too wordy, in my opinion, but they contains nuggets of wisdom. a. Peter F. Drucker, "The Essential Drucker: The Best of Sixty Years ..." b. Roger Fisher, et al, "Getting to Yes" c. William Ury, "Getting Past No" (sequel to "Getting to Yes")

Good luck.