Formal/Academic:
* Polyglot: This term is typically used for someone who speaks multiple languages. It could be used in this context, but might be considered slightly inaccurate as it doesn't explicitly indicate that the languages are dialects.
* Multilingual: Similar to polyglot, but again, might be too broad for this specific case.
* Dialectal expert: This is a more specific term, emphasizing the expertise in different dialects.
* Dialect specialist: Similar to the previous option, focusing on the expertise rather than just speaking ability.
Informal:
* Dialect aficionado: This term implies a passion and interest in dialects.
* Dialect buff: A more casual and playful term for someone who enjoys dialects.
* Dialect whiz: This term highlights the person's skill and knowledge of various dialects.
Ultimately, the best term to use depends on the specific context and the desired level of formality.