In Phoenician writing, unlike that of abjads such as those of Aramaic, Biblical Hebrew and Arabic, even long vowels remained generally unexpressed, regardless of their origin (even if they originated from diphthongs, as in bt 'house'; Hebrew spelling has byt). Eventually, Punic writers began to implement systems of marking of vowels by means of "matres lectionis". In the 3rd century BC appeared the practice of using final 'ālep to mark the presence of any final vowel and, occasionally, of yōd to mark a final long .