What is a vowel in linguistic terms?

A vowel, in linguistic terms, is indeed a speech sound produced with an open vocal tract. This means that when articulating a vowel, the airflow is not obstructed by the tongue, lips, or any other parts of the vocal apparatus, allowing for a clear sound to be made. Vowels are crucial in forming syllables and are typically the nucleus of a syllable, providing the necessary vocal sound around which consonants can cluster.

The nature of vowel sounds is such that they can vary significantly in terms of quality and tone; they can be short, long, high, low, rounded, and unrounded, depending on the position and shape of the mouth during pronunciation. This quality makes them distinct from consonants, which typically involve a constriction or closure at some point in the vocal tract.

In contrast to the other options, which do not accurately capture the essence of what defines a vowel, option B highlights the fundamental characteristic of vowels that differentiates them from other types of speech sounds.