A noteworthy difference in the Northern and Southern Lenape dialects was that the latter possessed the three phonetic elements _n_, _l_ and _r_, while the former could not pronounce the _r_, and their neighbors, the Mohegans, neither the _l_ nor the _r_. The dialect studied by Campanius and Penn, and that in southern New Jersey presented the _r_ sound where the Upper Unami and Minsi had the _l_. Thus Campanius gives _rhenus_, for _lenno_, man; and Penn _oret_, for the Unami _wulit_, good. The dialectic substitution of one of these elements for another is a widespread characteristic of Algonkin phonology. Roger Williams early called attention to it among the tribes of New England.[159] Tracing it to its origin, it clearly arises from the use of "alternating consonants," so extensive in American languages. In very many of them it is optional with the speaker to employ any one of several sounds of the same class. This is the case with these letters in Cree, which, for various reasons, may be considered the most archaic of all the Algonkin dialects. In its phonetics, the _th_, _y_, _l_, _n_ and _r_ are "permuting" or "alternating" letters.[160] Often, too, the sound falls between these letters, so that the foreign ear is left in doubt which to write. That this is the case with the Delaware is evident from some of the more recent vocabularies where the _r_ is not infrequent. The following words, from the vocabulary in Major Denny's _Memoir_, illustrate this:-- Stone _seegriana_ Buffalo _serelea_ Beaver _thomagru_ Above _hoqrunog_, etc. Even Mr. Lewis A. Morgan, who had considerable practice in writing the sounds of the Indian languages, inserts the _r_ in a number of pure Delaware words he collected in Kansas.[161] Another difficulty presents itself in the sibilants. They are not always distinguished. Mr. Horatio Hale writes me on this point: "In Minsi, and perhaps in all the Lenape dialects, the sound written _s_ is intermediate between _s_ and _th_ (the Greek _Θ_). This element is pronounced by placing the tongue and teeth in the position of the theta, and then endeavoring to utter _s_". The guttural, represented in the Moravian vocabularies by _ch_, was softened by the English likewise to the _s_ sound, as it appears also to have been by the New Jersey tribes.[162] In connection with dialectic variation, the interesting question arises as to the rapidity of change in language. With regard to the Lenape we are enabled to compare this for a period covering more than two centuries. To test it, I have arranged the subjoined table of words culled from three writers at about equidistant points in this period. Each wrote in the orthography of his own tongue, and this I have not altered. The words from Campanius are from the southern dialect, which preferred the _r_ to the _l_, and this substitution should be allowed for in a fair comparison. COMPARISON OF THE DELAWARE AT INTERVALS DURING 210 YEARS.