An Italian speaker confirms here that it can be used in that way: http://forum.wordreference.com/showthread.php?t=2104458
Thus, you have to rely on context to determine whether
nipoti is referring to just grandchildren, just the nephews/nieces, or all of the above. :) Hope this helps.
Because it's hasn't been programmed into the database. I check the drop down hints to see how the wind is blowing. Here there is no mention of nieces and nephews so I used grandchildren. It's not possible for Duo to have every possible version of every sentence so it usually has one correct but it gives the hints to help. (sometimes the hints are wrong)
According to Wiktionary here https://en.wiktionary.org/wiki/Appendix:Proto-Indo-European/n%C3%A9p%C5%8Dt népōt (a reconstructed form, of course) was already there in Proto-Indo-European, and the original meanings were a) grandchild, b) decendant and c) (possibly) nephew. The text adds that the meaning "nephew" is confined to the west and centre of the Indo-European world. The link between "grandson" and "nephew" (or, as in Irish, "sister's son") seems to be "descendant", possibly grandsons and sister's sons had the same position in the relationship hierarchy? Thus, English "nephew" is not a Romance loan (from French or Latin) but nefa was already there in Old English. "Nepotism", however, is a loan (from French népotisme, from Italian nepotismo, from Latin nepōs (“nephew”)). I use "nepotism" as a mnemonic aid for "nepote/nepoti".
my mother in law told me that nipote means nephew, niece, grandson and granddaughter to help differentiate when speaking about grandchildren we add ino or ina to the word so if you want us to be specific in the plural grandchildren would be nipotini - I had used we have eighty nephews and nieces
Actually nipotino/a/i/e is just a diminutive form of nipote. It has the same meaning, except it is used for little kids or as an affectionate form of nipote. Someone's grandchildren/nephews/nieces might be either little kids or not and might be called either by affectionate name or not. It still all depends on context.
In some languages (as in Russian) there's actually no difference between brother/sister (брат/сестра) and cousin. They just add an adjective if they want to mean specifically cousin (двоюродный/ая, once-removed). In English the case of in-law relatives is similar: son/daughter/brother/sister/father/mother-in-law, any of which might have a different name in other languages.
In some languages (as in Bulgarian) there are different words for mother's-brother (вуйчо), father's-brother (чичо), mother's-sister's-husband (калеко), father's-sister's-husband (свако) all of which would be called uncle in English. The same is for aunt and for all sorts of other relatives. We just have to accept what each language offers or requires.