And this too has causes known to grammarians and morphologists: frequent usage, the transfer of certain word forms, or other factors. As specialists in grammar and morphology know, the strongest vowel is damma (u), the lightest is fatha (a), and kasra (i) lies between them.

The language follows this pattern in both inflected and uninflected words. An inflected word that constitutes an indispensable core element of the sentence takes the nominative, as with the subject and predicate of a nominal sentence, the subject of a verb, and the object that takes its place in a passive construction. A supplementary element takes the accusative, as with the object, the circumstantial qualifier, and the accusative of specification. What occupies an intermediate position—because either a core element or a supplementary element may be annexed to it—takes the genitive: this is the second term of a possessive construction.

The same applies to uninflected words. Thus, they say of ayna (where) and kayfa (how) that their endings are fixed with fatha to ease pronunciation because of the yā’. Likewise, in the vocalization of fixed forms, the stronger takes damma and the weaker takes fatha. They say kariha al-shay’a (he disliked the thing), and for dislike they use karhan, with fatha, as Allah Most High says:

“To Him submits whoever is in the heavens and the earth, willingly or unwillingly.”

And He says:

“Come, willingly or unwillingly.”

The same applies to the contrast between kasra and fatha. For something slaughtered or taken as booty, they say dibh and nihb, with kasra, as Allah Most High says:

“And We ransomed him with a great sacrifice.”

And as it occurs in the hadith:

“Camels taken as booty were brought to the Messenger of Allah, may Allah bless him and grant him peace.”

And in the familiar proverb:

“I hear the millstones clattering, but see no flour.”

Here tihn is pronounced with kasra; that is: I see no