I'd like to trade in a specific language only

[marcelpanse]

Make a new trade setting: tradingLanguage with the default being "All languages". Someone can change their setting to a specific language. When you do, the trading matches page will only suggest people that also set their trading language to the same language.

This way you can easily find others that want to trade cards only in a specific language.

[nicolasfeyer]

I support this idea. Trading language matters a lot when exchanging cards, and this would make matches much more relevant.

Keeping “All languages” as the default avoids breaking anything, while letting people who care about a specific language easily find each other.

[greg19]

I think we could

ALTER TABLE accounts ADD COLUMN language CHAR(2);

to store the user main language (in ISO 639-1 format). Then just showing it on the user trading page will already be a big improvement.