* It's not a very common situation: In many parts of the world, being monolingual is unusual.
* The focus is often on languages spoken, not the number: We usually talk about someone being a "native speaker of English" or "fluent in Spanish," rather than focusing on the number of languages they speak.
* It can be seen as negative: Describing someone as "only speaking one language" can be perceived as limiting or suggesting a lack of cultural awareness.
Instead of using a specific label, it's often more appropriate to describe the situation:
* "They are a monolingual speaker."
* "They are fluent in [their language] but don't speak any other languages."
* "They are a native speaker of [their language]."
Remember, it's important to be respectful of everyone's language skills and cultural backgrounds.