In this project, when the green flag is clicked, the Scratch Cat should say "Meow, meow, meow!" in a speech bubble and as a sound. What you do to fix this issue, is replace the "Play sound Meow" block with a "Play sound Meow until done" block. Then place both blocks (the "Play sound Meow until done" block and the "Say Meow, meow, meow for 2 seconds" block) and put the talking block after the "Play sound Meow until done" block. (Reminder, these blocks are both inside the "Repeat 3 times" block)
Thanks to ScratchEdTeam for the original project Debug-It 1.5. Puffin_Rose (me)