A dot is used to mark the boundary between two syllables. Core syllables comply with the following basic design. The nucleus, which constitutes the backbone of every syllable, is required in all languages. In the vast majority of languages, nuclei have to be vowels or diphthongs. For example, english allows sonorant consonants to function as syllable nuclei in words such as rhythm or pickle. A consonant that functions as a syllable nucleus is marked by the diacritic [ ] and is often dubbed a syllabic consonant". All languages allow an onset consisting of at least one consonant to the left of the nucleus, and some even require that every syllable have an onset. Many languages permit a coda consisting of one or more consonants to the right of the nucleus, but many ban codas altogether, and no language requires that every syllable have a coda.