For 10 points, name these phonemes, which in English were subject to a "great shift" from 1400 to 1700 and are represented by the letters A, E, I, O, U, and sometimes Y.
These entities, when combined with the coda, form the rime. High examples of them have low F1 values while low examples have higher F1 values. They can be rotacized or "R-colored," which changes how their formants are perceived. Otto Jespersen studied these sounds, of which there are five in Esperanto and eight in Nahuatl. When one of them combines with another, the result is a diphthong. For 10 points, name these phonemes, which in English were subject to a "great shift" from 1400 to 1700 and are represented by the letters A, E, I, O, U, and sometimes Y.
These entities, when combined with the coda, form the rime. High examples of them have low F1 values while low examples have higher F1 values.
vowels [accept nucleus until "high"]