Final answer:
In General American (GA) pronunciation, the wh- sound in words like what, why, and which typically merges with the w sound, known as the whine-wine merger, making the distinction to the traditional /ʍ/ sound rare.
Step-by-step explanation:
When considering the pronunciation of wh- words in General American (GA) dialect such as what, why, and which, it's worth noting that in GA pronunciation, the wh- sound often merges with the w sound. This means that rather than pronouncing wh- as a distinct sound, many speakers in America will pronounce these words with just the w sound, so what sounds like wat, why sounds like wai, and which sounds like wich. This phonetic occurrence is known as the whine-wine merger.
In General American, the traditional distinction that used to be made in pronouncing wh- as /ʍ/ (a voiceless labio-velar approximant) is not generally maintained. Instead, most speakers pronounce wh- as /w/, making it sound identical to the w at the beginning of words like wet or win. Nevertheless, there are still some dialects within the United States that maintain the distinction.