Final answer:
The pronunciation of the vowel [ae] is undergoing a shift for many speakers in California.
Step-by-step explanation:
According to Cheng et al. (2016), the pronunciation of the vowel [ae] (as in 'cat', 'trap', and 'hand') is undergoing a shift for many speakers, particularly White and Black speakers, in California. The vowel [ae] is being pronounced as [e] or [ea] in certain contexts. For example, instead of saying 'cat' with a [ae] sound, some speakers may say 'ket' with an [e] sound. This phenomenon is known as the California Shift, and it has been documented in various studies on language variation.