What is the definition of a syllabic consonant?

A syllabic consonant is defined as a consonant that serves as its own syllable. This means that in certain phonetic contexts, a consonant is able to carry the syllabic weight typically associated with vowels, allowing it to act as the nucleus of a syllable.

For instance, in English, the consonant "l" in the word "bottle" can function as a syllabic consonant in its unstressed form, resulting in the pronunciation [ˈbɒt.əl] where the "l" sound fulfills the role of the vowel in that syllable. This characteristic sets syllabic consonants apart from regular consonants that usually require a vowel to complete a syllable.

The other options do not accurately define a syllabic consonant: a vowel standing alone is not relevant to this context, and a consonant appearing only at the beginning of a word does not address its potential to act as a syllable. Furthermore, a sound that cannot be pronounced without a vowel describes a different relationship between consonants and vowels, rather than the specific function of a syllabic consonant.