Arabic loan words have played a fundamental role in the evolution of New Persian. Persian in turn has transmitted the bulk of these loan words-together with its own modifications and rules for their incorporation-throughout the Islamic cultural area, playing midwife at the emergence of several Turkic and Indian literary languages.
In one class of Arabic loans, the modification of form in Persian has produced an intriguing puzzle. Some 1500 substantives ending in the Arabic feminine marker -a have assumed one of two forms in Persian-pronounced either with final t or with a vowel, and written respectively with "long t" and "silent h" (e.g., hekmat `wisdom; adage' and jomleh `total; sentence'). Is there a rationale behind this split?

In what is the first in-depth study of an old problem, the author demonstrates that the -at/-eh split takes its cue not from Arabic (where the alternation -at/-a is purely a matter of syntax) but from intuitive semantic categories and lexical developments in Persian. He shows, moreover, how hundreds of -at words shifted to -eh in the course of the past millennium, to reflect a shift in meaning; illustrates the evolution of "doublets" such as qovvat/qovveh; and explains why -at and -eh words in Tajik, Turkish and Urdu do not always correspond in form to their Persian cognates.
Though concerned with fundamentals of Persian lexicology and language history, this is also a unique case study of relevance to general theories of semantics and the lexicon.