[1] Take, for instance, the Celtic word _dúno-n_, Latinised _dunum_, which is the Irish _dún_ "castle" or "fortress," so common in Irish topography, as in Dunmore, Dunsink, Shandun, &c. There are over a dozen instances of this word in France, nearly as many in Great Britain, more than half a dozen in Spain, eight or nine in Germany, three in Austria, a couple in the Balkan States, three more in Switzerland, one at least (Lug-dun, now Leyden) in the Low Countries, one in Portugal, one in Piedmont, one in South Russia.
Celtic was once spoken from Ireland to the Black Sea, although the population who can now speak Celtic dialects is not more than three or four millions. As for Celtic archæological remains "on les trouve tant dans nos musées nationaux (en particulier au Musée de Saint Germain) que dans les collections publiques de la Hongrie, de l'Autriche, de la Hesse, de la Bohême, du Würtemburg, du pays de Bade, de la Suisse, de l'Italie." (Bertrand and Reinach, p. 3).
[3] Κελτός. The Greeks, the Latins, and the Celts themselves pronounced Kelt, as do the modern Germans. It is against the genius of the French language to pronounce the _c_ hard, but not against that of the English, who consequently had better say Kelt.
[5] As is proved, according to Jubainville, by its having made its way into German before the so-called Laut-verschiebung took place, to the laws of which it submitted, for out of Celtis, the feminine form of it, they have made Childis, as in the Frank-Merovingian Bruni-Childis or Brunhild, and the old Scandinavian Hildr, the war-goddess.
[6] This was actually a living word as recently as ten years ago. I knew an old man who often used it in the sense of "spirit," "fire," "energy": he used to say _cuir gal ann_, meaning do it bravely, energetically. This was in the county Roscommon. I cannot say that I have heard the word elsewhere.
[7] Thus the Greek ὑπέρ, Latin s-uper, German über is _ver_ in ancient Celtic (_for_ in Old Irish, _ar_ in the modern language), platanus becomes litano-s (Irish leathan), παρά becomes _are_, and so on.
[8] Lhuyd's "Comparative Etymology," title i. p. 21. Out of over 700 pages in O'Reilly's Irish dictionary only twelve are occupied with the letter _p_.