Celtic | +-----------+-----------+ | | Gadelic Brittonic | | +------+------+ +-------+-------+ | | | | | | Irish Manx Gaelic Welsh Cornish Breton The main difference between those two branches is, that in Gadelic the original guttural of the Aryan tongue came gradually to be _c_ with the sound _k_, ogam _qu_, and that in Brittonic it became _p_. So we say:— English Gaelic Welsh Latin Four _c_eithir _p_edwar quatuor Five _c_oig _p_imp quinque Such a distinction points to a great change from the common speech of earlier Celtic times. It existed prior to the Christian era, and is still strikingly in evidence. Edward Lhuyd, the illustrious Welsh antiquary, writing in the early part of the eighteenth century, noted that there were scarcely any words in the Irish that began with _p_, beyond what were borrowed from Latin or some other language. So much was this the case, that in an ancient alphabetical vocabulary which he had beside him, the letter _p_ was entirely omitted. Other instances might be given. For example, in O’Reilly’s Irish Dictionary, out of upwards of 700 pages, only twelve are occupied with that letter; and when we come to examine the most recent Gaelic collection of words—the etymological dictionary of Dr. Macbain—we find about 270 beginning with _p_ out of a total of well over 7000; and even of these, the majority are derived or borrowed from Norse or English. There is a MS. of the eighteenth century in the Laing collection of Edinburgh University, which puts the case succinctly, when in the sections of what promised to be a good Gaelic grammar, it observes that of old no word, except _exotic_ words, began in Gaelic with a _p_. Fastening on so characteristic a distinction Professor Rhys, some years ago, decided to call the Brittonic the P, and the Gadelic the Q group, as the more simple and fundamental classification. Thus far philology helps to differentiate between the two branches, and points to a remote advent of the Gael in Britain.