A new TCA field type called language was added to TYPO3 Core with v11.2. Its main purpose is to simplify the TCA language configuration. It therefore supersedes the special=languages option of TCA columns with type=select as well as the now mis-use of the foreign_table option, being set to sys_language.

Since the introduction of site configurations and the corresponding site languages back in v9, the sys_language table was not longer the only source of truth regarding available languages. Actually, the languages, available for a record, are defined by the associated site configuration.

The language field type therefore allows to finally decouple the actually available site languages from the sys_language table. This effectively reduces quite an amount of code and complexity, since no relations have to be fetched and processed anymore. This also makes the sys_refindex table a bit smaller, since no entries have to be added for this relation anymore. To clean up your exisiting reference index, you might use the CLI command bin/typo3 referenceindex:update.

Another pain point was the special -1 language which always had to be added to each TCA configuration manually. Thus, a lot of different implementations of this special case could be found in one and the same TYPO3 installation.

The new TCA type now automatically displays all available languages for the current context (the corresponding site configuration) and also automatically adds the special -1 language for all record types, except pages.