1884, Prof. John Avery, “Notes from Oriental Periodicals” in The American Antiquarian and Oriental Journal, volume VI, ed. Stephen Denison Peet, Chicago: F.H. Reveell, № 1 (January 1884), ‘[Notes from the] Journal of the Anthropological Institute, August, 1883’, page 66:
We observe that languages differ greatly in their propensity to use abstract and concrete terms — some using the former freely, others the latter; and between the two extremes is every shade of intermediate usage. This tendency is best illustrated by terms of relationship; thus, in some languages parents call their children sons and daughters — abstract terms; in others they speak of them as male and female children — concrete terms. […] This peculiarity of expression [Dr. Gustav Oppert of Madras] has adopted as the basis of a classification of speech into abstract and concrete languages. […] Concrete languages are divided into heterologous, or those which contain special words, used when persons of different sex address each other; and homologous, or those in which both sexes use the same words. […] Abstract languages are classified under two heads, digenous and trigenous; that is to say, those which recognize two genders, and those which recognize three.
