When a user creates a duplicate account (both Person Account and Business Account) with the exact same details, no duplicate record alert is prompted. The user language is not set to English.
This is expected. The Soundex comparisons, which is used by the Account Wizard, only work for the English language.
By design, the New Account Wizard only searches for duplicates if the user language is set to English.
CRM Help Documentation: Duplicate Record Checking in Account Wizards