At present the default installation of Tuskfish is only available in English (Thai is on the way) but this is easy to fix:

• Make a copy of the file trust_path/libraries/tuskfish/language/english.php and give it the name of your own preferred language. For example, for Thai you would create trust_path/libraries/tuskfish/language/thai.php.
• Translate all the English phrases into your own language.
• Add the new language to listLanguages() in trust_path/libraries/tuskfish/class/Tfish/Traits/Language.php:

public function listLanguages(): array
{
    return [
        "en" => "English",
        "th" => "Thai",
    ];
}

The new language will appear as an option in Admin => Settings => Preferences => Edit => Default languag. Selecting it will convert your site interface.