First step : you need to check if the targeted language is activated. To check it, follow this way : Settings > Languages > Add language and then add the targeted language.

Chart of accounts update :

If several languages are activated in the database, a field “EN” should be displayed next to the record where a translation can be applied.

If you click on this “EN” field (EN meaning english), you will be able to update the translation manually. 

Then, the translation applied on this account will be based on the preferences of the user. Please find a little video demo to see the differences between the preferences : https://watch.screencastify.com/v/jX1sGLBZDmXsq96iQJ00

It’s also possible to update all your accounts in one-shot with an import. When you are realizing the import, the language of your user should be the one of the targeted language. For example, all my chart of accounts is in English (US) but I want to update it in French (BE) / Français (BE). Before the import, I need to be sure that my user has the language French (BE) / Français (BE) applied in my profile. Once I import, Odoo will detect the language of the user and will apply the appropriate translation. 

Please see an all flow with French (BE) / Français (BE) and Spanish (AR) / Español (AR) translations import : https://watch.screencastify.com/v/0BNNlUSnhGrHBXpybqtq

Balance sheet item update :

Basically it will be the same as for the accounts, but no translation import will be possible. You will need to do it manually.

First step, you need to activate the developer mode (Settings > Developer Tools > “Activate the developer mode”) to find the Financial reports under the configuration menu in the accounting app (Accounting > Configuration > Management > Financial reports). 

Inside the report, you will find the same field “EN” meaning that translations can be applicable on this record.

If you drill down inside the report, you will find the sections where you can update the translations.

By clicking on this “EN” field, you will find the translations applied once the user’s profile is updated with this language. In this example, I added "ODOO CUSTO" myself.

Once you have applied the translations, the report will be updated automatically based on the language of the user. Please see the video including the example above : https://watch.screencastify.com/v/YMjkpT5a3HISynozsYll

I hope this is clear for you and that translations inside the accounting app will no longer be an issue !