[…] [the effect of conceptual association] stands in the foreground of neogrammarian studies. It is cited as the antithesis to the regularity of sound laws, as the "psychological" factor in contrast to the "physiological" factor [...] Thus we are forced from every side to recognize that regularity is inherent in the psychological as well as the physiological linguistic principle. In other words, we are obliged to coordinate the two. The peripheries of their spheres of influence intersect each other at many points [...] Thus the antithesis melts away before our eyes and the problematic character of the external relationship between the two factors [physiological factor and psychological factor] becomes clear when we understand their internal relationship correctly. (p. 43)
- Schuchardt (1972)

Within the totality of analogical phenomena the activity of conceptual associations can scarcely be delimited with any certainty. In languages in which all words are now stressed upon the first syllable, it was originally only the greater number that were so stressed inasmuch as the first syllable is also the most significant. Did the majority go to work wholesale upon the minority, or, did the change progress quite gradually, taking place at each step only between conceptually related words? At times the conceptual relationship is such a general one that it is easily overlooked. (p. 46)
- Schuchardt (1972)