Translation:The students will learn in the class but I will not learn.
Sentences like these make me realize that spelling bees in Irish would be murder.
English makes some distinction between "the students in the class will learn" (which students will learn) and "the students will learn in the class" (where the students will learn.) Does an Ghaeilge? Duolingo accepts both answers.
I’d think that the former meaning would require a relative clause in Irish, e.g. Foghlaimeoidh na daltaí atá sa rang (“The students who are in the class will learn”).
You can hear the root word foghlaim pronounced on Duolingo in the exercise Tá mo mhac ag foghlaim na Gaeilge, though it's worth listening to the different pronunciations on teanglann.ie too - the Munster pronunciation is noticeably different.
The future tense 1st person plural Foghlaimeoimid is also spoken in this exercise, but it's probably not of much help to you.
Where is the "the" for "in the class" in this sentence? Why is "The students will learn in class" not acceptable?
"sa" means "in the".
The English phrase "in class" is usually translated into Irish as "sa rang", but when translating in the other direction, from Irish to English, "sa rang" is usually translated as the literal "in the class", unless the context clearly indicates that that would be wrong, which isn't the case here.
Can one not say "in class" or does this strictly mean a specific classroom?
It depends on what you mean: she was in class all afternoon bhí sí sa rang an tráthnóna ar fad or bhí ranganna aici ar feadh an tráthnóna; If you mean "in class" as opposed to in" real life" you would probably have to express it without rang.