It is better to say that Sindarin is "inspired" by Welsh. The phonology is quite close (though simpler), the grammar is similar in many respects (though again, simpler; eg, _peth_ 'word(s)' changes to _beth_ in _lasto beth lammen_ 'listen to the words of my tongue' because it is the object of the sentence); the vocabulary, however, is almost entirely different, having been related initially to the words of Qenya, which was invented first.

Quenya is less easy to categorize. It has resonances with Finnish, Latin (and Spanish), Greek, and even (at its earliest stage) with Gothic. Again, primarily in sounds, less so in grammar, and least of all in vocabulary (though moreso than Sindarin, eg, tie 'path' which is also Finnish).

Adunaic does have a triconsonantal root-structure, like the Semitic languages. See _The Drowning of Anadune_ in 'Sauron Defeated' (v9 of HoME). The Dwarvish language even moreso.