{{temp|t-SOP}}

Perhaps we should use {{t}} instead of {{tø}} for SOP translations? It works well and is easy to convert from accelerated translations (just adding [ [ ] ]).

They don't work any different for cases like this. They all use the same Module:translations and the only difference between them is in the "interwiki" parameter, which is "tunk" for {{t}}, "tpos" for {{t+}}, "tneg" for {{t-}} and empty for {{tø}}. But the code on lines 36 to 40 will set the interwiki parameter to empty if links are found in the text (with the assumption that we don't want interwikis for SOP terms), so all four templates behave like {{tø}} in this case.

As I recall the only reason we had separate templates for the different interwiki cases was to avoid an expensive switch statement. Do you think we should just merge all the t templates now that it's all in Lua?

There is no immediate rush to delete them as they all use the same module anyway, and the only difference is the interwiki parameter. Essentially, your proposal means to transfer the interwiki parameter from the three templates into all the entries. We could do that, but we'd have to add that parameter and convert all translations, which could take a long time. The current situation is ok.

We could get rid of {{tø}} because the module is able to detect (to what accuracy I don't know) which languages can have valid interwikis. That would leave {{t}}, {{t+}} and {{t-}}. Personally, I would like to merge them all into {{t}}, and abandon the practice of changing the display of interwikis depending on whether the foreign Wiktionary has an entry. It's not really a huge usability issue (how many people even use those links anyway?) and we need bots to constantly update {{t}} into either {{t+}} or {{t-}}, which just isn't being done and will probably never be done.