[Galin]

One minor question: when did Eriol learn the elf-tongue? Or, to put it another way, what language are they speaking in this tale? I assume--and I might be drawing off half-digested knowledge of later chapters--that they are speaking Elven (what would later be called Quenya), but as far as this chapter goes, there's no real evidence that I recall. For that matter, the Elves seem remarkably blasé about this human wandering around in their midst.

Yes, in The Music of the Ainur ('intro' of sorts) Eriol states that he had learned:

'that one fair tongue which the Eldar speak about this Isle of Tol Eressea -- but I marvelled to hear you speak as if there were many speeches of the Eldar: are there so?"

'Aye,' said Rumil, 'for there is that tongue to which the Noldoli cling yet -- and aforetime the Teleri, the Solosimpi, and the Inwir had all their differences. Yet these were slighter and are now merged in that tongue of the Island Elves which you have learnt.'

The early Qenya Lexicon is noted 'in the dialect of Kortirion'. I can't say that every early text will give the same account of tongues, necessarily, in all details, but in any event Eriol is talking to Rumil who had himself already 'worried at whiles even over the tongues of Men'

I suppose, within the context of the Cottage chapter, Eriol had learned during his journeying before he arrived at the Cottage? At the moment I can't recall if this is noted anywhere. Anyway, in a later 'Elfwine scenario', Elfwine arrives in Tol Eressea to find that his own tongue is spoken there.