Al, I'm not trying to mislead you in any way. You're right, I don't own the model but I got the instructions directly from LG customer support. Someone has already asked the same question in the past and have confirmed that the instructions worked for him.
Link: How to turn off keypad tones on the LG GB-255G?
You can contact LG directly for further assistance.
Grindale, your answers are incorrect. Many of your answers do not correlate with the menus that I see on my LG GB255g. I believe you don't even own this model. It is not nice to provide misleading anwers.
Go to Profiles and choose a profile to edit then follow these steps:
Press Personalize > Touch and Key Feedback > Touch and Key Tones > Off