Gesenius' Hebrew Grammar/Additions and Corrections/177
Rem. According to the prevailing view, this strengthening of the first radical is merely intended to give the bi-literal stem at least a tri-literal appearance. (Possibly aided by the analogy of verbs פ״ן, as P. Haupt has suggested to me in conversation.) But cf. Kautzsch, ‘Die sog. aramaisierenden Formen der Verba ע״ע im Hebr.’ in Oriental. Studien zum 70. Geburtstag Th. Nöldekes, 1906, p. 771 ff. It is there shown (1) that the sharpening of the 1st radical often serves to emphasize a particular meaning (cf. יִגָּר, but יְגֹרֵ֫הוּ, יָחֵל and יַחֵל, יִסֹּב and יָסֹב, יִשֹּׁם and תֵּשַׁם), and elsewhere no doubt to dissimilate the vowels (as יִגָּר, יִדַּל, never יָגַר, יָדַל, &c.): (2) that the sharpening of the 1st radical often appears to be occasioned by the nature of the first letter of the stem, especially when it is a sibilant. Whether the masoretic pronunciation is based on an early tradition, or the Masora has arbitrarily adopted aramaizing forms to attain the above objects, must be left undecided.