[…] cumulative character of the signs of relationship, the uncertain value of any single item, and the need of historical evidence to support their interpretation, set limits to the reach and competence of linguistic investigation.
- Whitney (1875), a pag.268

[…] most general and grandest of movements of signification, which carries words over from a more material and substantial value toward one that is more conceptual and formal […].
- Whitney (1875), a pag.114

That our written vowels have from three to nine values each, is owing to the fact that we have altered their original unitary sounds in so many different ways during the historic period […].
- Whitney (1875), a pag.56