One of the most peculiar features of the people of Borneo is the great
diversity of language obtaining among them. The migratory habits of
the people and the consequent mingling of communities of different
stocks within the same areas, far from having resulted in the genesis
by fusion of a common language, have resulted in the formation of
a great number of very distinct dialects; so that in following the
course of a river, one may sometimes find in a day's journey of a
score of miles half a dozen or more villages, the people of each of
which speak a dialect almost, or in some cases quite, unintelligible
to their neighbours. A necessary consequence of this state of affairs
is that, with the exception of the Sea Dayaks, almost all adults
speak or at least understand two or more dialects or languages,
while most of the chiefs and leading men speak several dialects
fluently and partially understand a larger number. The language most
widely understood by those to whom it is not native is the Kayan;
but since the recent spread of trade through large areas under the
protection of the European governments, a simplified form of the Malay
language has been rapidly establishing itself as the LINGUA FRANCA of
the whole country. In Sarawak, where, during the last fifty years,
the Sea Dayaks have spread from the Batang Lupar district and have
established villages on all the principal rivers, their language,
which seems to be a bastard and very simple branch of the Malay tongue,
is very widely understood and is largely used as a common medium.

Note on the use of the term KLEMANTAN. The Malay name for Borneo is
Pulu Klemantan, and we have adopted this name to denote the large
group of allied tribes which in our opinion have the best claim to
be regarded as representing the indigenous population of the island.