"It is true that my grandfather is more than seventy years old."

Translation: È vero che mio nonno ha più di settant'anni.

[sc_acc]

From "Grammatica Italiana di Base", Trifone, Palermo 2000, p. 81 "Con gli altri nomi di parentela, l'ommissione dell'articolo e' possibile, ma non obbligatoria: mia nonna/la mia nonna." "Il mio nonno" should be accepted here, and in other cases where it is not.

[giuliap]

It might be acceptable, but in 23 years living in Italy I've never heard anybody saying that, except in old books. Sometimes what is grammatically correct can be so dated to the point of sounding wrong.

[sc_acc]

I don't understand how that impacts my request. The simple fact is that it is listed as correct... in more than one Italian grammar reference. Here's another: "Per alcuni nomi di parentela, per esempio, 'nonno' e 'nonna', l'uso e' oscillante, nel senso che si puo' avere o non avere l'articolo: "la mia nonna o mia nonna" - Grammatica Italiana Con Nozioni Di Linguistica, Dardano/Trifone, 1999. That's not too old, either.

The software should accept grammatically correct answers. If Duolingo wants to suggest a preferred solution, they can do so. But they should attempt to accept all grammatically correct solutions.

[jeporcher]

Thanks for the info! I got accustomed to using the article and Duolingo tells me I'm wrong time and time again. Good to know it is not widely use in common parlance, though.

[Chris123456]

Interesting opinions in this discussion and I can see both points of view. Personally, I am more than happy that Duolingo has taught me to stop putting the article in such phrases. If it is no longer in common use why bother learning it? Languages evolve and time-expired phraseologies need to rest in peace.

[amanda185]

I've also never heard of the article being used with nonna/nonno...I've heard it's optional with mamma and papa'...and it's only used with loro and further removed relatives (like fratellastro, etc.)... And anyway, I think it's best to learn good habits and go along with what's currently considered correct.