In which family of languages word roots are not themselves syllables or words, but instead are isolated sets of consonants?
In Arabic, the root meaning "write" has the form k-t-b. From this root, words are formed by filling in the vowels, e.g. kitāb "book", kutub "books", kātib "writer", yaktubu "he writes" etc. Most scripts used to write Semitic omit some or all of the vowels, because the consonants are the primary carriers of meaning.