Baldur,
The fragmentation of the original language could be simply from occupation and assocation with these other languages. Like many languages, including english, some words just are not explainable in one language and must tap into an older language to facilitate the understanding.
Possible Example in Klyron:
Dsthenduso "Meeting place"
'ei "At, or There"
Elthurian (a random river)
In klyron: You and I will go to Dsthenduso 'eiElthurian River
In old tounge (unfragmented and held intact by a few elders) could be something like this:
"Incandis dsthenduso'eiElthurian ianc'alhana"
Together At River Elthurian meeting place we join.
Cracking crucial ties between words is important. like 'Incandis' and 'Ianc', both pertaining to us, we, together, connected, ect If you want to really break it down you could say they derive from 'an' (which is in both words and alhana (join)), meaning 'bound' or 'parts of'. Keeping that stream of thought you could apply it to anything and then just branch forward and backward in old tounge and 'new tounge' and discover thier roots and thier new counterparts in the current dialect.
It could also be assumed that after enough exposure there would surely be new generations that have but completely parted from the old language, hanging on to bits and pieces they hear in every day conversation, not really knowing what the names of the places really mean in thier native language.
tired. must rest.
fair well,
k-