Ya is the twenty-eighth and last letter of the modern Arabic order and the tenth of the older abjad order, from which it takes the numeral value ten. Standing alone or at the end of a word it is a shallow bowl with a hooked tail and two dots below; joined at the beginning or in the middle it contracts to a tooth carrying its two dots beneath, the same shape as ba, ta, tha and nun with different pointing.
Ya is a moon letter. Like waw it works as both consonant and vowel, writing the y of English and the long vowel i, and roots containing it behave irregularly in the verb system for the same reason.
Written at the end of a word without its two dots, ya is a different thing again: it is called alif maqsura, the shortened alif, and it stands for a long a rather than a long i. Whether a final letter of that shape carries dots is therefore a matter of spelling that changes the sound, and the convention is not uniform, since Egyptian printing has commonly left the dots off ordinary final ya while other traditions print them. That is one of the small differences that tell a reader where an edition was produced.
Its name descends from the Northwest Semitic yod, the cognate of Hebrew yod and Syriac yudh, whose sense was hand, and it holds the numeral value ten that Hebrew yod holds. Ya is one of the fourteen letters that appear disjoined at the head of a sura.