No sound notification for text for a contact

Hello D Jeffrey,

Welcome to Apple Support Communities. First, you want to make sure that this contact wasn't inadvertently muted in Messages. Go to Messages, and go to the message thread from that contact. If there is a bell icon with a line through it, that contact is muted. Swipe left on that message thread and tap "Unmute". You can get more info on using Messages here:

Use Messages on your iPhone or iPad - Apple Support

Feel free to reach back out if you have any questions.

We hope this helps you.