GMAT Critical Reasoning (CR) | Re: Xani and Yata are the only two languages Source:Powerscore

Premise : Xani and Yata are the only two languages spoken in the country of Zorba, with Xani spoken by the majority of Zorba’s residents.
Conclusion : Thus, by learning Xani prior to visiting Zorba, tourists can feel confident that they have done the most that they can to assist in communicating with Zorba’s locals.

I'm looking for an assumption, i.e. a statement that must be true.

(A) Travelers to Zorba will not visit other countries in addition to Zorba. Off-topic
...

---