Today’s pronunciation question is: “Can you explain why the sound /a/ is different in cash and wash?”
Sure. That is a great question! I will respond in two parts:
1. why the same vowel is different in two words
2. why the same vowel in the same word is different at times
Why is the same vowel sound different between two words?
Speech sounds, especially vowels which do not have a specific “place” of articulation (i.e. your tongue does not touch a specific place in the mouth), are influenced by the sounds around it. A /w/ sound is a semi vowel meaning it has properties of BOTH vowels and consonants. So the /w/ sound influences the /a/ sound making it sound slightly different. In this case, the vowel will be made with more rounded lips than it would in the word cash.
This also happens in words with sounds made through the nose like M, N, NG. The vowel becomes a bit nasal. This would result in the /a/ in can sounding different than the /a/ in cab.
Why are the same vowel pronounced differently in different sentences or at different times?
In English, we stress syllables or words by making the vowel longer. This makes even the vowel in the same word sound different depending on stress. For instance, You make a lot of CASH versus You make a LOT of cash. The vowel in the stressed CASH will be longer than in the unstressed cash.