"Whose pen is this?"
Translation:Kies skribilo estas tio ĉi?
For the record:
I just (2016-03-19 22:49 [CET]) received an e-mail stating
You suggested “Kies skribilo ĉi tiu estas?”
as a translation for “Whose pen is this?”
We now accept this translation. :)
(Hopefully it was for this question, as the e-mail didn't contain a link to it.
I'm also unsure of whether they've added other word-order-variants, such as "Kies skribilo estas tiu ĉi?", of it as well.)
On the contrary: your English looks just fine to me, but the Esperanto is wrong - tio is a pronoun and so stands by itself instead of a noun; it can't come before a noun like an adjective or a determiner. (While in English, "this" can be either a pronoun or a determiner.)
It's a bit like the difference between your (determiner) and yours (pronoun) - you can say "This is your pen" and "This (one) is yours" but you can't say "This is yours pen" any more than you can say tio skribilo.
I'm not sure what you mean with "that", but perhaps the following may be helpful:
- on the difference between correlatives in -u and those in -o (e.g. tiu, tio)
- on correlatives in -u in general
- on correlatives in -o in general
These are from PMEG, a description of Esperanto grammar in Esperanto.
It is sometimes used before a noun as a sort of demonstrative determiner: ĉi libro.
I don't think it can ever stand by itself as a demonstrative pronoun.
But most commonly, it is used together with a ti- correlative: ĉi tiu, tiu ĉi, ĉi tiel, tiel ĉi, etc.
(Or sometimes hyphenated to an adjective or adverb, as in ĉi-somere, ĉi-sube, ĉi-landa.)