Currently, when selecting a language that has a converter, Special:Translate requires the user to select something else. It is just a plain-text error message. Here's an example from Kazakh:

https://commons.wikimedia.org/wiki/File:Kazakh_translatewiki_error_asking_to_translate_into_kk-cyrl.jpg

It could be more user-friendly. Some immediate ideas:

• Don't allow selecting languages that can't be targets in ULS.
• Change the plain-text message to direct links to translating in the variants.
• Redirect the user to the default variant.

There could be some more improvements.