See https://english.stackexchange.com/questions/4325/using-that-and-this-interchangeably and related questions there and elsewhere on the internet.
As far as I know "ta/to/ten" are more like "the/that". Actually it should be a kind of "not defined distance". If you want to say "this" It would be "tahle" or "tato".
"Jak vysoká je tahle/tato osoba?"
Signed: student of Czech language trying to share the knowledge of my native Czech teacher.
Thank you, that does clarify this somewhat :) I speak Polish (which is fairly similar to Czech) and we also use "ta, to, ten" which roughly covers "this, the" (usually the object being close to you) and "tamta, tamto, tamten" which would be more "that" (object being farther away than "this"), it's all confusing... :P
In Czech, "ten, ta, to" is used for "undefined" distance mostly, sometimes for further away, but rarely for close to the speaker.
"tamten, tamta, tamto" is specifically used for long distance "that ... over there"
"tento, tato, toto" (colloquially "tenhle, tahle, tohle") is used specifically for objects close to the speaker.