I. COHERENCE AMONG LINGUISTIC FUNCTIONS
According to Meumann, the whole field of language is a unit, psychologically considered. Reading, spelling, composition, the learning of foreign languages should thus be intimately interconnected for a given individual. He who learns one readily, should also readily learn the others, without notable exception.
This view of the close coherence among linguistic functions is borne out, also, by the work of Gates, already cited, in which he found high positive correlations among perceptual tests which use words as materials.
We must notice, nevertheless, that the correlations fall considerably short of unity. Illustrative cases show that occasionally children are found who can read well, but cannot spell legibly, though the present writer has not seen cases of the opposite condition, and has not found them reported in the literature.
Special defect in spelling will, therefore, be given separate consideration, though it must be recognized that abilities in spelling and reading are usually closely associated.