If you're talking about the variation in language:
* Standard language: This refers to the officially recognized, codified form of a language, often used in formal settings like government and education.
* Formal language: This is the opposite of slang or informal language and is often used in writing and official contexts.
* Universal language: This refers to a language spoken by a large number of people, usually across geographical borders.
If you're talking about regional variations in language:
* Universal language: As mentioned above, a language spoken by a large number of people across geographical borders.
* International language: A language used for communication between people of different countries, such as English or French.
If you're talking about a distinct way of speaking:
* Clarity: This suggests a way of speaking that is easily understood by a wider audience.
* Standard pronunciation: This refers to the accepted pronunciation of a language, often used in dictionaries and teaching materials.
Ultimately, the best antonym for "dialect" depends on the specific context in which it's being used.