There are tons of popular programming languages and they share paradigms, good ideas and syntactic similarities. Query languages ought to be the same.
Dialects work in natural language because interpretability, syntax and semantics are all fuzzy.
Dialects in computer languages is an anti-pattern because syntax and grammar must be precise and deterministic. You are either writing Java or gibberish, the Java toolchain will never charitably interpret your syntax errors as "close enough to understand".
SQL-the-standard birthed a bunch of different dialects of SQL that ought to be de-jure separate query languages.
So much human effort is wasted dealing with the standard SQL abstraction layer. If someone is migrating from Oracle to Postgres, the fact that their query languages are eerily similar is far down the list of practical concerns.