What is primarily related to the transition portion of formant frequencies?

The transition portion of formant frequencies primarily relates to consonants because it is during consonant production that changes in formant frequencies occur very quickly. This is particularly evident in the articulation of stop consonants, fricatives, and affricates, where there is a distinct movement in the vocal tract that results in abrupt shifts in formant patterns. These transitions help to signal the presence of consonants in speech and are crucial for differentiation between various phonemic sounds.

In contrast, vowels typically have more stable formant frequencies with less dramatic transitions because they are produced with a relatively open vocal tract, allowing for sustained sounds. Diphthongs, while they do involve some transition as they move from one vowel quality to another, do not specifically pertain to the rapid changes associated with consonant production. Nasals have their own distinct acoustic properties, but they don't emphasize the rapid transitions of formant frequencies in the same way consonants do. Thus, the nature of consonant articulation makes it the primary focus when discussing transitions in formant frequencies.