Have you seen https://commons.wikimedia.org/wiki/Template:Closed_captions#Localization

To add your language to the list of languages supported by this template, please copy the code of Template:Closed captions/en (or any other language version you prefer to translate) and replace the text strings in there (the form below can be used to create a translation, the English version is preloaded in the edit box). Please change the parameter lang from en (or whatever language you are translating) to the language code of your language.

Both https://commons.wikimedia.org/wiki/Template:Closed_captions/nyo and https://commons.wikimedia.org/wiki/Template:Closed_captions/ttj need creating from https://commons.wikimedia.org/wiki/Template:Closed_captions/en or similar.

In T354201#9430623, @Reedy wrote:

Both https://commons.wikimedia.org/wiki/Template:Closed_captions/nyo and https://commons.wikimedia.org/wiki/Template:Closed_captions/ttj need creating from https://commons.wikimedia.org/wiki/Template:Closed_captions/en or similar.

Will do, thank you!

Update: Template:Closed captions/nyo and Template:Closed captions/ttj have been created, however the problems mentioned in the feature summary still exist

In T354201#9431809, @TheDJ wrote:

nyo and ttj are not language codes that are supported/known to Mediawiki and thus not accepted by timedmediahandler. This ticket is similar to T345870

T354212 has recently been created

This (and T345870) should be solvable by adding the languages to InitialiseSettings' wmgExtraLanguageNames until Translatewiki localization is completed; no problem with that from Langcom side.

ttj is available on Commons now.

In T354201#9464828, @jhsoby wrote:

Nyoro is also available on Commons now.
Good job, @Ahiise2!

Thank you!