"When will you buy them?"

Translation: Utavinunua lini?

[Leigh_Anne_]

Is ki/vi noun classed used when the object isn't specified?

[AGreatUserName]

Generally the N/N class (9/10) is used as a default for inanimate things (-i-/-zi-), but there is quite a bit of regional variation. The ki-vi class (7/8) is sometimes used.

In this case, I'd say it's referring to something of class 8, such as viatu "shoes", or viazi "potatoes" ... but if you've just said vitu vile "those things", this would be appropriate too.

[nayrad]

Commenting so I know when someone answers

[leighforbes]

Ditto! How do we know which class of infix to use when the object isn't specified?

[snadhelta]

Ditto.

[ChristianL298842]

Ditto. We must know!

[aboutpurpo]

They don't have a place to enter this comment, but either a) or b) should be accepted. They are a) utavinunua lini? and b) utavinunua lini?? I know there shouldn't be two question marks, but the phrase is still correct.

[BeelerFami]

without specific reference to the object, any of the object-noun plural prefixes should work...
-ya-, -zi-, -vi-, -i-. reported 3/19