'Tochter' must come from a very, very old Proto-Indo-European word indeed. In Persian, the word for daughter is دختر or Dochter. Through the millennia, only a consonant has changed.
Indeed. Wiktionary notes that they descend "from Proto-Indo-European *dʰugh₂tḗr (compare Ancient Greek θυγάτηρ (thugátēr), Gaulish duxtīr, Tocharian A ckācar, Tocharian B tkācer, Lithuanian duktė̃, Armenian դուստր (dustr), Persian دختر (doχtar), Sanskrit दुहितृ (duhitṛ))". (the * in front means 'theoretic reconstruction').
Names for family members are fairly strongly conserved in general; terms for 'male child' are also quite similar across IE languages--compare (again from Wiktionary) English son, Dutch zoon, Afrikaans seun, Low German sone, German Sohn, Danish søn, Swedish son, Icelandic sonur , Lithuanian sūnùs, Russian сын (syn), Avestan hūnuš, Sanskrit सूनु (sūnú), Ancient Greek υἱύς (huiús), Albanian çun, Armenian ուստր (ustr), Tocharian B soy, soṃśke ....
It's really interesting how several English and German words with shared roots have changed the letter d for a t . die Tür - the door die Tochter - the daughter trinken - drink dass - that ...
Now I'm curious about learning how/when this change took place
@Gnorian : Please look at the tables in the following link: http://www.canoo.net/inflection/mein:Pron:Poss:1st:SG
Why when I wrote My daughter eats noodles it got accepted when Nudeln is pasta.
it could work, depending on the type of pasta. Some types of pasta, such as spaghetti and fettuccine are both pasta and noodles. All noodles are pasta, but not all pastas are noodles.