According to Louis Ginzberg's Legends of the Jews, the twenty-four book canon of the Hebrew Bible was fixed by Ezra and the scribes in the Second Temple period. According to the Talmud, much of the Tanakh was compiled by the men of the Great Assembly (Anshei K'nesset HaGedolah), a task completed in 450 BCE, and it has remained unchanged ever since. The 24-book canon is mentioned in the Midrash Koheleth 12:12: Whoever brings together in his house more than twenty four books brings confusion. Language and pronunciation The original writing system of the Hebrew text was an abjad: consonants written with some applied vowel letters ("matres lectionis"). During the early Middle Ages, scholars known as the Masoretes created a single formalized system of vocalization. This was chiefly done by Aaron ben Moses ben Asher, in the Tiberias school, based on the oral tradition for reading the Tanakh, hence the name Tiberian vocalization. It also included some innovations of Ben Naftali and the Babylonian exiles. Despite the comparatively late process of codification, some traditional sources and some Orthodox Jews hold the pronunciation and cantillation to derive from the revelation at Sinai, since it is impossible to read the original text without pronunciations and cantillation pauses. The combination of a text ( mikra), pronunciation ( niqqud) and cantillation ( te`amim) enable the reader to understand both the simple meaning and the nuances in sentence flow of the text. Number of different words used The number of distinct words in the Hebrew Bible is 8,679, of which 1,480 are hapax legomena, words or expressions that occur only once. The number of distinct Semitic roots, on which many of these biblical words are based, is roughly 2000. Books of the Tanakh The Tanakh consists of twenty-four books, counting as one book each 1 Samuel and 2 Samuel, 1 Kings and 2 Kings, 1 Chronicles and 2 Chronicles, and Ezra–Nehemiah. The Twelve Minor Prophets () are also counted as a single book. In Hebrew, the books are often referred to by their prominent first words. Torah The Torah (, literally "teaching") is also known as the "Pentateuch", or as the "Five Books of Moses". Printed versions (rather than scrolls) of the Torah are often called ( "Five fifth-sections of the Torah") and informally as . (, literally "In the beginning") – Genesis (, literally "The names of") – Exodus (, literally "And He called") –