Need some advice ahead of an AC regarding languages

Summary:

Interviewing for a private banking analyst position based in London and the role requires Arabic language proficiency. While I was born in Dubai and can speak the language well enough to not sound like a foreigner when in arabic-speaking countries, I would certainly struggle to discuss the markets or particular investment ideas in Arabic.

I'm wondering whether this will be tested at the assessment centre as I will be able to improve the language on the job however not in time for the interviews.

Also, if someone could clarify whether I would be advising investors from Arabic countries looking to invest into western opportunities or advising any investors on investing into the Arab markets.

Thank you