I find it difficult to control my pitch and now Im wondering if I’ve been using the same trick as you without realizing it. My parents used to tell me “stop whining” and I’d be like “Im not complaining about anything?” Its been a while since my parents said that. Maybe they’ve just accepted it. Maybe it’s because my voice has gotten a bit deeper from smoking (yikes). To answer your question though, I don’t see the harm in continuing what you do if it only annoys your mom. If other people are giving you a hard time then maybe reevaluate. Its my opinion that saying the words you want clearly but with an ‘annoying’ voice, is better than not getting the message out at all.