Hi @user77220,

I agree with what @Fiat Lux - ASIA stated above. I'll share with you the steps you need to add an accountant in QuickBooks Online (QBO) International.

Here's how:

1. Sign in to your QBO company as a master admin. 
2. Go to the Gear icon.
3. Select Manage users.
4. Click Add user, then choose Company admin.
5. Ensure you select This user is my accountant.
6. Tap Next.
7. Enter your accountant's name and email address, then hit Save.

Please be advised, you can have one accountant user per QBO company at most. For your other question about the language used by the system, you can select one. This specific language you set will be the same for all users of the same QBO company, including your accountant. So the option to have a different language set between users of the same QBO company is unavailable. 

You can also view this article for your reference: Add and manage users in QuickBooks Online. Scroll down at the bottom of the page to see a list of FAQs along with recommended steps to resolve them.

If you have other questions about this process or anything in particular about QBO International, then post a comment below. I'll get back to you as soon as I can.