I've ALWAYS experienced this! I remember as a young boy mulling over the word "piano". Peeyaaaanooooo... it doesn't mean anything....
Also, in speech, I'll often forget common words and be reaching for them but they're mysteriously absent!!
"To wake up in the morning, I set my...... my...... oh for crying out loud, what's that thing called??"
[coworker looks at me with revulsion] "...Alarm clock?"
"Yeah. That. Sheesh! Stupid brain of mine."