* Part of speech: This refers to the grammatical category of a word (e.g., noun, verb, adjective).
* A sound: This is a specific sound in the English language.
The question is a little tricky because it's not clear if you're asking about:
1. The sound "A": Does the word "part" or "speech" contain the sound "A"? The answer is yes.
2. A sound made when saying "part of speech": This is more complex. The entire phrase does not contain the distinct sound "A" in the way that "cat" does.
Let me know if you had a specific sound in mind, and I can help you further!