"Can you understand Irish?"
Translation:An féidir leat an Ghaeilge a thuiscint?
Is it possible to say "an féidir leat na Gaeilge a thuiscint?" here? Instead of "an féidir leat Gaeilge a thuiscint?" the first wasn't accepted.
Nope, because Gaeilge isn't a plural. You can use an Ghaeilge, however, which is what's shown as the translation here.
an Ghaeilge is the nominative, when speaking abouy the language in a broad sense. na Gaeilgej is genitive. as Gaeilge is when you speak as Gaelige*