Question: does a word have to have a vowel

Answer: No, English has words written without the five conventional vowel letters (A, E, I, O, U); it also has words without spoken vowel sounds. In most languages of the world, all or nearly all lexical words have vowel sounds, and English is no exception; however, rhotic dialects of English (such as most varieties of American English) have words like nurse and word with a syllabic r sound, but these words are written with a vowel letter immediately prior to an r. On the other hand, there are words that are not written with any of the five conventional vowel letters, though they are pronounced with a vowel sound. There also are some interjections and besides onomatopoeia, to ideophones in general, that contain neither vowel sounds nor syllabic r and which are thus spelled without a vowel letter.