Science

These tip-of-the-tongue experiences are a normal part of human language experience across the life span, and they increase as you grow older. One proposed reason for this increase is that they’re due to an age-related disruption in the ability to turn on the right sounds needed to say the selected word.

Very interesting perspective. That your brain identifies the conceptual word information but can't identify the linguistic factual word. Makes sense, and validates the feeling of "I know it" without being able to actually know it.

Are there any studies about how the ability to retrieve words differ across generations?

Whenever I watch the old interviews with random people on the street on TV, I'm astonished by how articulate the people were in the past, compared to the present.